assignment on natural resources class 9

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NCERT Solutions for Class 9 Science Chapter 14 Natural Resources

NCERT Solutions Class 9 Science Chapter 14 Natural Resources – Here are all the NCERT solutions for Class 9 Science Chapter 14. This solution contains questions, answers, images, step by step explanations of the complete Chapter 14 titled Natural Resources of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 14 Natural Resources. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 14 Natural Resources in one place. For a better understanding of this chapter, you should also see Chapter 14 Natural Resources Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 14 Natural Resources:

• Natural Resources
• The Breath of Life: Air
• Water: A Wonder Liquid
• Mineral Riches in the Soil
• Biogeochemical Cycles
• Ozone Layer

These solutions are part of NCERT Solutions for Class 9 Science . Here we have given Class 9 NCERT Science Textbook Solutions for Chapter 14 Natural Resources.

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Question 2. How does the atmosphere act as a bblanket? (SA II – 2012, 13) Answer: It is a known fact that, air is a bad conductor of heat and our atmosphere contains mainly the air. Due to this reason, the atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the course of the whole year. The atmosphere prevents the sudden increase in temperature during the daylight hours and during the night, it slows down the escape of heat into outer space.

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Question 3. What causes winds ? (SA II – 2012, 13) Answer:  Winds are caused due to unequal heating of atmospheric air. This phenomena can be easily seen near coastal regions during the daytime. The air above the land gets heated faster and starts rising. As this air rises, a region Of low pressure is created and air over the sea moves into this area Of low pressure. The movement of air from one region to the other Creates winds. During the day, the direction of the wind would be from the sea to the land.

Question 4. How are clouds formed ? (SA II – 2013) Answer: The water evaporates due to heating up Of water bodies and other biological activities. The air also heats and rises. On rising, it expands and cools to form tiny droplets. These droplets grow bigger, expand and form clouds. The collection Of dust and other suspended particles facilitate the process.

Question 5. List any three human activities that you think would lead to air pollution. (SA II – 2013) Answer:  Human activities that would lead to air pollution (i) Excessive use and burning of fossil fuels like coal and petroleum produces different oxides of nitrogen and sulphur. These are not only dangerous to our respiratory system but also leads to acid rain. (ii) Incomplete combustion of various fuels forms unburnt carbon particles which lowers the visibility, especially in cold weather when water also condenses Out of air. This is known as smog and is a visible indication Of air pollution. (iii) Large usage Of automobiles and improperly tuning of engines leads to the formation of carbon monoxide gas and Other oxides of nitrogen which causes lot of respiratory problems. (iv) Forest fires, excessive mining and ore refining, excessive use of chlorofluorocarbons and excessive industrialisation leads to air pollution.

Page 194: Question 1. Why do organisms need water ? (SA II – 2012) Answer:  Organisms need water due to the following (i) All cellular processes take place in a water medium. (ii) All the reactions that take place within our body and within the cells occur between substances that are dissolved in water. (iii) Substances are also transported from one part of the body to the other in a dissolved form. (iv) Water makes up about 70% of body weight Of all living organisms. (v) It helps in the digestion of food and absorption of nutrients in the blood. Hence, organisms need to maintain the level of water within their bodies in order to stay alive. It helps in maintaining body temperature. Question 2. What is the major source of freshwater in the city/town/village where you live ? Answer:  The major sources of freshwater in the city (town/ village is the underground water which is mostly taken out with the help of hand pumps or tube wells. The rivers flowing in the nearby areas, lakes and ponds also serve as the source of freshwater.

Question 3. DO you know any activity which may be polluting these water sources? Answer:  There are many activities which cause pollution Of water sources such as : (i) Dumping of waste from factories, sewage from our towns and cities into rivers or lakes. (ii) Discharging hot water from cooling towers into the water bodies affect the breeding capacity of aquatic organisms.

Page 196 Question 1. How is soil formed ? (SA II – 2013, 2014) Answer:  The formation of soil takes place in this way : Over long periods of time, thousands and millions Of years, the rocks at or near the surface of the are broken down by various physical, chemical and some biological processes. The end product of this breaking down is the fine particles of soil. There are many other factors which play a vital role in the formation of soil. These factors are : (i) The Sun : It causes heating of rocks which causes cracking and ultimately breaking up into smaller pieces. (ii) Water: It breaks rocks both by freezing and fast flow. (iii) Wind : It causes erosion of rocks similar to as done by fast flowing water. It also carries sand from one place to the other like water does. (iv) Living organisms : Lichens and moss plants grow on the rock surface and cause rock surface to powder down and form a thin layer of soil. The roots of big trees sometimes go into cracks in the rocks and as the roots grow bigger, the crack is forced bigger.

Question 2.What is soil erosion ? (SA II 2012) Answer:  The removal of topsoil which is rich in humus and nutrients by flowing water or wind is known as soil erosion. If this process continues further then all soil may get washed away and the rocks underneath may get exposed. It may lead to the loss of all valuable resources because nothing grows as such on the rocks.

Question 3. What are the methods of preventing or reducing soil erosion ? (SA II – 2012) Answer:  The methods of preventing soil erosion are : (i) Afforestation : Forests reduce erosion as the roots of trees hold the soil in place. (ii) Shelter belts : Trees planted in lines or hedges around farmland reduce erosion by reducing the speed of the wind. (iii) Contour ploughing : Farmers plough land so that furrows lie across the natural slope of the land. These furrows trap water and do not allow it to flow down carrying the topsoil. (iv) Terrace (or step) farming : A terraced hillside is less likely to be eroded than a natural hillside. Here a series of steps formed by horizontal strips supported by walls, catch the descending water. It gives the water sufficient time to percolate into the soil and nourish the crop. (v) Soil cover : Soil left bare after harvesting a crop is often covered with dried vegetation to prevent erosion. Steep slopes that cannot be ploughed are covered with grass or pasture crops. (vi) Preventing overgrazing : As the grass has a tendency to bind soil molecules, so even a very little grass on a field prevents erosion of soil. But if the grass is overgrazed, it exposes the soil to erosion.

Page 201 Question 1. What are the different states in which water is found during the water cycle? (SA II – 2011) Answer:  All three different states of water can be seen during the water cycle. These states are : (i) Gaseous state (In the form Of water vapour which evaporates from the surface water). Liquid state (It is formed by the condensation of water vapour and can be Seen in the form of rain). (ii) Solid state (It is formed by the freezing Of liquid droplets in the upper layer of atmosphere which can be seen in the form Of snow, hail Or sleet).

Question 2. Name two biologically important compounds that contain both oxygen and nitrogen. (SA II – 2011) Answer:  Proteins and nucleic acids (DNA and RNA).

Question 3. List any three human Which would lead to an increase in the carbon dioxide content of air. (SA II – 2011) Answer:  Three human activities which would lead to an increase in the C02 content of air are : (i) Respiration : It is the natural process Of release Of C02 by both plants and animals. But this release is neither dangerous nor it has any adverse effect on our environment. (ii) Combustion of fuels : The various types of fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial fuels. (iii) Deforestation : Trees help in the conversion Of C02 into organic compounds such as glucose, starch, etc., by the process of photosynthesis. When these trees are cut non-judiciously, then the level of C02 increases in our environment.

Question 4. What is the greenhouse effect ? (SA II – 2011) Answer:  Some gases prevent the escape of heat from the Earth. An increase in the percentage Of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect.

Question 5. What are the two forms of oxygen found in the atmosphere ? (SA II 2011) Answer:  (i) Elemental oxygen is normally found in the form Of a diatomic molecule (02) in the lower regions Of the atmosphere to the extent of 21 %. It is non-poisonous form Of oxygen. (ii) But in the upper reaches Of the atmosphere (stratosphere), it occurs in the form of ozone, containing three atoms of oxygen and having the molecular formula 03. It is the poisonous form of oxygen. Some other forms of Oxygen : It also Occurs extensively in the combined form in the Earth’s crust as well as also in the air in the form of carbon dioxide. In the crust, it is found as the oxides of most metals and silicon, and also as carbonate, sulphate, nitrate and other minerals. It is also an essential component Of most biological molecules like carbohydrates, proteins, nucleic acids and fats (or lipids).

Question 1. Why is the atmosphere essential for life (SAII – 2011) Answer: Atmosphere is essential for life because of the following masons : (i) It keeps the average temperature of the earth fairly steady during the day and even during the course of the whole year. (ii) It prevents the sudden increase in temperature during the daylight hours. (iii) It contains all the important gases which are required for sustaining life on earth. These gases are : (a) Oxygen for respiration of living organisms and oxidation. (b) Carbon dioxide for photosynthesis in plants and for making food. (c) Nitrogen for providing inert atmosphere and making proteins. (iv) The stratosphere region (16-23 km from the surface of Earth) of atmosphere contains a thick layer of ozone which filters the harmful UV radiation from Sun. If these radiations reach on the surface of Earth, then they may cause cancer in animals and are also harmful for plants.

Question 2. Why is water essential for life ? (SAII – 2011) Answer:  Water is considered essential for life because of the following reasons : (i) All cellular processes take place in water medium. (ii) All the reactions that take place within our body and within the cells occur between substances that are dissolved in water. (iii) Substances are also transported from one part of the body to the other in a dissolved form. (iv) Water makes up about 70% of body weight of all living organisms. (v) It helps in the digestion of food and absorption Of nutrients in the blood. Hence, organisms need to maintain the level of water within their bodies in order to stay alive. (vi) It helps in maintaining body temperature.

Question 3. How are living organisms dependent on the soil? Are organisms that live in water totally independent Of soil as a resource ? Answer: Living organisms are dependent on the soil in the following ways : (i) Soil provides a natural habitat for various different organisms (such as bacteria, fungi, algae) which help in improving the quality of the soil. Thus, they maintain the fertility of the soil. (it) Number of insects, animals like rats, rabbits, etc., build their home in the soil. (iii) Earthworms perform all their activities in the soil. They maintain fertility also as their excreta is rich in nitrogen. (iv) Soil provides anchorage and nutrients to the plants for their growth and development. Yes, all organisms that live in water are totally dependent on soil as a resoure : The mineral nutrients are present in water in the dissolved form. But their recycling takes place only with the help Of decomposers which are present in the soil beds. Thus, all water bodies has soil beds which contain decomposers for the recycling of nutrients and to convert them into readily absorbable forms.

Question 4. You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather? Answer:  Weather observatories collect information regarding the pattern of temperature, speed of wind, air pressure, ocean features and all other features which can affect the weather. This information is collected by remote sensing and weather forecasting satellites. The information collected is then sent to the meteorological departments which prepare a weather report which is displayed on the maps. This information is further transmitted through radio and television.

Question 5. You might have heard about weather report saying ‘depressions’ in the Way of Bengal have caused rains in some areas. We know that many human activities lead to increasing levels of pollution of the air, water bodies and soil. Do you think that isolating these activities to specific and limited areas wcwld help in reducing pollution ? Answer:  Yes, definitely if these activities are isolated to specific and limited areas, then the level of pollution Of the air, water bodies and soil will ‘decrease. For example (i) If all the sewage discharge, industrial waste is collected and treated properly before diScharging into water bodies, then obviously aquatic life in these water bodies will be affected to a little extent. (ii) If hot water from the industries (which is used for cooling machines and other devices) is collected at a common place and cooled and aerated properly before discharging into water bodies. Then this will not affect the breeding capacity of aquatic organisms. (iii) If all the industries and commercial places of a city/town are located in a particular area which is far away from a residential area. Then all diseases resulting from air pollution could be minimised. (iv) Above all, if we use only biodegradable substances, then they will get decomposed easily and there will be very little pollution of our precious natural resources.

Question 6. Write a note on how forests influence the quality “four air, soil and water resources. Answer: Forests influence the quality of air, soil and water resources in the following ways :

• Influence of forests in controlling the quality of air : (a) Forests help in minimising the level of C02 in the atmosphere. This prevents greenhouse effect and global warming. (b) Forests reduce environmental temperature which in turn increases the rate of photosynthesis in plants in the surrounding regions. (c) Some of the trees has the ability to absorb harmful gases present in the atmosphere, e.g., Jamun trees can absorb compounds of lead easily.
•  Influence of forests in controlling the quality of soil : (a) The roots of huge trees larger area and prevent erosion of topsoil by holding the soil particles tightly. (b) Forests also regulate biogeochemical cycles which are responsible for cycling of nutrients and making them available for the plants in the soil, (c) Many of the decomposing bacteria and nitrogen-fixing bacteria live in close association with the roots of the trees.
• Influence of forests in controlling the quality of water : (a) Forests help in returning pure water back to the surface of earth through rains (b) Forests help in maintaining the water cycle as well as water resources of the earth.

NCERT Solutions for Class 9 Science Chapter 14 Natural Resources (Hindi Medium).

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Natural Resources Class 9 Notes

Chapter 14 Natural Resources 

Earth is the only place where life exists. Earth's resources are land, water and air. Other resources include fossil fuels, sunlight, wind and minerals. Biological factors refer to organisms in an ecosystem. Air, water and soil form the abiotic or abiotic components of the biosphere.

NCERT notes for Grade 9 Science are ready to help students easily understand all concepts. Natural Resources is an important chapter in the biology section of the 9th grade science curriculum. Vidyakul's academic experts have addressed the questions in this chapter and presented them in an easily understandable way for all students.

These NCERT notes help students complete assignments on time. The notes also helps you quickly review chapters before exams. Students can learn more about energy sources by reading the article.

CBSE CLASS 9th CH-14

Points to remember.

Given below are the important points for NCERT notes on Class 9 Science Chapter 14:

Air pollution is caused by the introduction of pollutants, organic molecules, or other unsafe materials into Earth’s atmosphere

Causes: Man-made sources include combustion of fuel, smoke from industries, Burning crackers etc. Natural sources include forest fires, volcanoes, etc.

Effects: Respiratory diseases, Global warming, Acid Rain, etc.

The ozone layer is the thin part of Earth's atmosphere that serves to protect Earth's stratosphere and absorbs most of the sun's ultraviolet (UV) radiation. The ozone layer has a higher concentration of ozone (O3) than the rest of the atmosphere.

Biogeochemical = Biological Chemical + Geological Process

The circulation and transformation of carbon between living things and the environment is called the Carbon Cycle.

The nitrogen cycle is the recycling and reusing of nitrogen in different forms to meet the demands for various environmental activities.

It is a biological process which helps in maintaining the oxygen level.

Photosynthesis is a biological process used by plants to prepare their food with the help of sunlight and energy.

For more such important points, students can refer to Vidyakul.

Topics and Sub-topics

NCERT notes for Grade 9 Science Chapter 14's overarching topics will help students prepare for the exam. It is recommended that students complete all sections and subtopics. The "Energy Sources" chapter is easy to enter. Once the concepts are clear, students can carefully prepare for the exam. Vidyakul offers a variety of questions for CBSE Class 9 Science Chapter 14. Also, students can get really good grades if they learn the concepts easily.

Before jumping into further details, let us first look into the different sections and sub-sections included in this chapter:

Few Important Questions

What are the consequences of CFC emission?

Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and halons destroy the earth’s protective ozone layer, which shields the earth from harmful ultraviolet (UV-B) rays generated from the sun.

What are the steps in ‘Hydrologic cycle’?

The Hydrologic cycle is the water cycle and it consists of three major processes: evaporation, condensation and precipitation.

What are the uses of humus?

Humus allows water and oxygen to reach and feed plant roots. By allowing excess water to drain, organic material prevents vital nutrients from leaching out of the soil.

Learn more about in Natural Resources Class 9 Notes pdf.

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Related Links

• Chapter 1 - Matter in Our Surroundings
• Chapter 2 - Is Matter Around Us Pure
• Chapter 3 - Atoms and Molecules
• Chapter 4 - Structure of The Atom
• Chapter 5 - The Fundamental Unit of Life
• Chapter 6 - Tissues
• Chapter 7 - Diversity in Living Organisms
• Chapter 8 - Motion
• Chapter 9 - Force and Laws of Motion
• Chapter 10 - Gravitation
• Chapter 11 - Work and Energy
• Chapter 12 - Sound
• Chapter 13 - Why Do We Fall ill
• Chapter 14 - Natural Resources
• Chapter 15 - Improvement in Food Resources

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NCERT Solutions for Class 9 Science Chapter 14 Natural Resources

NCERT Solutions for Class 9 Science (biology) Chapter 14 Natural Resources are given below. In these solutions, we have answered all the intext and exercise questions provided in NCERT class 9 science textbook. Class 9 NCERT Solutions Science Chapter 14 provided in this article are strictly based on the CBSE syllabus and curriculum. Students can easily download these solutions in PDF format for free from our app.

Class 9 Science Chapter 14 Textbook Questions and Answers

INTEXT QUESTIONS

Question 1: How is our atmosphere different from the atmospheres on Venus and Mars?

Answer: Earth’s atmosphere is different from those of Venus and Mars. This difference lies essentially in their compositions. Earth’s atmosphere is a mixture of nitrogen (79%), oxygen (20%), and a small fraction of carbon dioxide, water vapours and other gases. This makes the existence of life possible on Earth. However, the atmospheres on Venus and Mars mainly consist of carbon dioxide. The amount of carbon dioxide on these planets can range from 95% to 97%.

Question 2: How does the atmosphere act as a blanket?

Answer: The atmosphere acts as a blanket by performing the following functions:

(a) It keeps the average temperature of the Earth fairly constant during day time and even during the course of whole year.

(b) It prevents a sudden increase in the temperature during day time.

(c) It slows down the escape of heat from the surface of the Earth into outer space during night time.

Question 3: What causes winds?

  Answer: The uneven heating of the earth’s surface is the main cause for the winds. On being heated more the air raises up and hence low pressure is created. Hence the air in high pressure occupy the low-pressure region causing the wind.

Question 4: How are clouds formed?

Answer: During day time, on being heated, a large amount of water evaporates from various water bodies and goes into the air. A part of this water vapour also reaches the atmosphere through biological activities such as transpiration and respiration. This causes the air in the atmosphere to heat up. 

When this heated air rises, it expands and cools, which results in the condensation of water vapour forming water droplets. The presence of dust and other suspended particles in air also facilitates the process of condensation. The formation of water droplets leads to the formation of clouds.

Question 5: List any three human activities that you think would lead to air pollution.

  Answer: The following three human activities would lead to air pollution: (i) Burning of fossil fuels such as coal and petroleum (ii) Industrialization (iii) Deforestation

PAGE NO 194

Question 1: Why do organisms need water?

Answer: Organisms need water for the following reasons:

(i) All cellular processes need water as a medium. Usually, the reactions that take place in our body or within the cells occur between substances that are dissolved in water.

(ii) Since most of the substances are transported in a dissolved form, water is necessary.

Question 2: What is the major source of fresh water in the city/town/village where you live?

Answer: River is a major source of fresh water.

Question 3: Do you know of any activity which may be polluting this water source?

  Answer: The discharge of waste water from homes, industries, hospitals, etc. into the river pollutes this fresh water source.

PAGE NO 196

Question 1: How is soil formed?

Answer: Soil is formed by breaking down of rocks at or near the surface of the Earth through various physical, chemical, and biological processes by various factors such as the sun, water, wind and living organisms.

Sun: During day time, the rocks are heated. This causes the rocks to expand. During night time, these rocks cool down and contract. Since all parts of the rock do not undergo expansion and contraction at the same rate, this causes the formation of cracks in these rocks. These cracks lead to the breaking up of huge rocks into smaller pieces.

Water: Water catalysis the process of formation of soil in two ways.

(i) Water goes into the cracks and crevices formed in the rocks. When this water freezes, its volume increases. As a result, the size of the cracks also increases. This helps in the weathering of rocks.

(ii) Running water wears away hard rocks over long periods of time. Water moving in fast speed carries big and small particles of rock downstream. These rocks rub against each other, resulting in breaking down of rocks. These smaller particles are carried away by running water and deposited down its path.

Wind: Strong winds carry away rocks, which causes rubbing of rocks. This results in the breaking down of rocks into smaller and smaller particles.

Living organisms: Some living organisms like lichens help in the formation of soil. Lichens also grow on rocks. During their growth, lichens release certain substances, which cause the rock surface to powder down forming a thin layer of soil. On this thin layer of soil, some small plants like moss also grow. They further cause the breaking down of the rock particles.

Question 2: What is soil erosion?

Answer: The blowing away or washing away of land surface by wind or water is known as soil erosion.

Question 3: What are the methods of preventing or reducing soil erosion?

Answer: The methods of preventing or reducing soil erosion are:

• Prevention of deforestation
• Plantation of trees

PAGE NO 201

Question 1: What are the different states in which water is found during the water cycle?

Answer: During the water cycle, water is found in solid state (snow, ice, etc.), liquid state (ground water, river water, etc.), and gaseous state (water vapours).

Question 2: Name two biologically important compounds that contain both oxygen and nitrogen.

Answer: Two biologically important compounds that contain both oxygen and nitrogen are:

• Amino acids
• Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)

Question 3: List any three human activities which would lead to an increase in the carbon dioxide content of air.

• Burning of fuels in various processes like heating, cooking, transportation, and industry.
• Human induced forest fires.
• The process of deforestation includes the cutting down of trees. This decreases the uptake of carbon dioxide for photosynthesis. Eventually, the content of carbon dioxide increases.

Question 4: What is the greenhouse effect?

Answer: Some gases like carbon dioxide, methane, nitro us oxide prevent the escape of heat from the Earth’s surface by trapping it. This increases the average temperature of the Earth. This is called the greenhouse effect. An increase in the content of such gases would lead to a situation of global warming.

Question 5: What are the two forms of oxygen found in the atmosphere

Answer: The two forms of oxygen found in the atmosphere are:

• Diatomic molecular form with chemical formula O 2 .
• Triatomic molecular form with chemical formula O 3 known as ozone.

Question 1: Why is the atmosphere essential for life?

Answer: The atmosphere is essential for life because it maintains an appropriate climate for the sustenance of life by carrying out the following activities:

(i) Atmosphere keeps the average temperature of the Earth fairly constant during day time.

(ii) It prevents a sudden increase in temperature during day time.

(iii) It also slows down the escape of heat from the surface of the Earth into outer space during night time.

Question 2: Why is water essential for life?

  Answer: Water is essential for life because of the following reasons:

(i) Most biological reactions occur when substances are dissolved in water. Thus, all cellular processes need water as a medium to take place.

(ii) Transportation of biological substances needs water as a medium.

Question 3: How are living organisms dependent on the soil? Are organisms that live in water totally independent of soil as a resource?

Answer: All living organisms on the earth directly or indirectly dependent on soil for a living. Plants obtain water and minerals through the soil and prepare their food. Other living organisms that live in water are entirely not totally independent of soil because the microbes growing on the soil in water are the primary producers. Primary producers are the main and chief element of the food chain. Various microbes found in soil help in the decomposition of dead plants and animals in water which helps in returning the nutrients and elements back to the water.

Question 4: You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?

Answer: Weather is studied as the collection of various elements like high and low temperatures, humidity, rainfall, wind speed and more using various figures and facts with relevant instruments. Hence on the data collected by the meteorologists, we are able to forecast the weather.

Question 5: We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution?

Answer: Yes. Isolating human activities to specific areas would help in reducing levels of pollution. For example, setting up of industries in isolated regions will control pollution to some extent. The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.

Question 6: Write a note on how forests influence the quality of our air, soil and water resources.

Answer: Forests influence the quality of our air, soil, and water resources in various ways. Some of them are:

(i) Forests balance the percentages of carbon dioxide and oxygen in the atmosphere. The increasing amount of carbon dioxide caused by human activities is balanced by a larger intake of carbon dioxide by plants during the process of photosynthesis. Simultaneously, a large amount of oxygen is released.

(ii) Forests prevent soil erosion. Roots of plants bind the soil tightly in a way that the surface of the soil cannot be eroded away by wind, water, etc.

(iii) Forests help in the replenishment of water resources. During the process of transpiration, a huge amount of water vapour goes into the air and condenses to form clouds. These clouds cause rainfall that recharge water bodies.

Class 9 Science NCERT Solutions Chapter 14 Natural Resources

CBSE Class 9 Science NCERT Solutions Chapter 14 helps students to clear their doubts and to score good marks in the board exam. All the questions are solved by experts with a detailed explanation that will help students complete their assignments & homework. Having a good grasp over CBSE NCERT Solutions for Class 9 Science will further help the students in their preparation for board exams and other competitive exams such as NTSE, Olympiad, etc.

NCERT Solutions for Class 9 Science Chapter 14 PDF

Below we have listed the topics discussed in NCERT Solutions for Class 9 Science Chapter 14. The list gives you a quick look at the different topics and subtopics of this chapter.

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NCERT Solutions for Class 9 Science Chapter 14 Natural Resources

These NCERT Solutions for Class 9 Science Chapter 14 Natural Resources Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.

Natural Resources NCERT Solutions for Class 9 Science Chapter 14

Class 9 scien ce chapter 14 natural resources intext questions and answers.

Question 1. How is our atmosphere different from the atmospheres on Venus and Mars? Answer: Earth’s atmosphere is different from those of Venus and Mars. This difference lies essentially in their compositions. Earth’s atmosphere is a mixture of nitrogen (79%), oxygen (20%), and a small fraction of carbon dioxide, water vapours and other gases. This makes the existence of life possible on Earth. However, the atmospheres on Venus and Mars mainly consist of carbon dioxide. The amount of carbon dioxide on these planets can range from 95% to 97%.

Question 2. How does the atmosphere act as a blanket? Answer: The atmosphere acts as a blanket by performing the following functions: (a) It keeps the average temperature of the Earth fairly constant during daytime and even during the course of whole year. (b) It prevents a sudden increase in the temperature during daytime. (c) It slows down the escape of heat from the surface of the Earth into outer space during nighttime.

Question 3. What causes winds? Answer: An uneven heating of the Earth’s surface causes winds. On being heated, air becomes lighter and rises up. As a result, a region of low pressure is created. Then, air from a high pressure region moves to a low pressure region, causing wind.

Question 4. How are clouds formed? Answer: During daytime, on being heated, a large amount of water evaporates from various water bodies and goes into the air. A part of this water vapour also reaches the atmosphere through biological activities such as transpiration and respiration. This causes the air in the atmosphere to heat up. When this heated air rises, it expands and cools, which results in the condensation of water vapour forming water droplets. The presence of dust and other suspended particles in air also facilitates the process of condensation. The formation of water droplets leads to the formation of clouds.

Question 5. List any three human activities that you think would lead to air pollution. Answer: The following three human activities would lead to air pollution:

• Burning of fossil fuels such as coal and petroleum
• Industrialization
• Deforestation

Question 6. Why do organisms need water? Answer: Organisms need water for the following reasons:

• All cellular processes need water as a medium. Usually, the reactions that take place in our body or within the cells occur between substances that are dissolved in water.
• Since most of the substances are transported in a dissolved form, water is necessary.

Question 7. What is the major source of fresh water in the city/town/village where you live? Answer: River is a major source of freshwater.

Question 8. Do you know of any activity which may be polluting this water source? Answer: The discharge of wastewater from homes, industries, hospitals, etc. into the river pollutes this freshwater source.

Question 9. How is soil formed? Answer: Soil is formed by breaking down of rocks at or near the surface of the Earth through various physical, chemical, and biological processes by various factor such as the sun, water, wind, and living organisms. (i) Sim: During day time, the rocks are heated. This causes the rocks to expand. During nighttime, these rocks cool down and contract. Since all parts of the rock do not undergo expansion and contraction at the same rate, this causes the formation of cracks in these rocks. These cracks lead to the breaking up of huge rocks into smaller pieces.

(ii) Water: Water catalyses the process of formation of soil in two ways. (a) Water goes into the cracks and crevices formed in the rocks. When this water freezes, its volume increases. As a result, the size of the cracks also increases. This helps in the weathering of rocks. (b) Running water wears away hard rocks over long periods of time. Water moving in fast speed carries big and small particles of rock downstream. These rocks rub against each other, resulting in breaking down of rocks. These smaller particles are carried away by running water and deposited down its path.

(iii) Wind: Strong winds carry away rocks, which causes rubbing of rocks. This results in the breaking down of rocks into smaller and smaller particles.

(iv) Living organisms: Some living organisms like lichens help in the formation of soil. Lichens also grow on rocks. During their growth, lichens release certain substances, which cause the rock surface to powder down forming a thin layer of soil. On this thin layer of soil, some small plants like moss also grow. They further cause the breaking down of the rock particles.

Question 10. What is soil erosion? Answer: The blowing away or washing away of land surface by wind or water is known as soil erosion.

Question 11. What are the methods of preventing or reducing soil erosion? Answer: The methods of preventing or reducing soil erosion are:

• Prevention of deforestation
• Plantation of trees

Question 12. What are the different states in which water is found during the water cycle? Answer: During the water cycle, water is found in solid state (snow, ice, etc.), liquid state (ground water, river water, etc.), and gaseous state (water vapours).

Question 13. Name two biologically important compounds that contain both oxygen and nitrogen. Answer: Two biologically important compounds that contain both oxygen and nitrogen are:

• Amino acids
• Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)

Question 14. List any three human activities which would lead to an increase in the carbon dioxide content of air. Answer:

• Burning of fuels in various processes like heating, cooking, transportation, and industry.
• Human induced forest fires
• The process of deforestation includes the cutting down of trees. This decreases the uptake of carbon dioxide for photosynthesis. Eventually, the content of carbon dioxide increases.

Question 15. What is the greenhouse effect? Answer: Some gases like carbon dioxide, methane, nitrous oxide prevent the escape of heat from the Earth’s surface by trapping it. This increases the average temperature of the Earth. This is called the greenhouse effect. An increase in the content of such gases would lead to a situation of global warming.

Question 16. What are the two forms of oxygen found in the atmosphere? Answer: The two forms of oxygen found in the atmosphere are:

• Diatomic molecular form with chemical formula O2.
• Triatomic molecular form with chemical formula O3 known as ozone.

Class 9 Science Chapter 14 Natural Resources Textbook Questions and Answers

Question 1. Why is the atmosphere essential for life? Answer: The atmosphere is essential for life because it maintains an appropriate climate for the sustenance of life by carrying out the following activities:

• Atmosphere keeps the average temperature of the Earth fairly constant during daytime.
• It prevents a sudden increase in temperature during daytime.
• It also slows down the escape of heat from the surface of the Earth into outer space during nighttime.

Question 2. Why is water essential for life? Answer: Water is essential for life because of the following reasons:

• Most biological reactions occur when substances are dissolved in water. Thus, all cellular processes need water as a medium to take place.
• Transportation of biological substances needs water as a medium.

Question 3. How are living organisms dependent on the soil? Are organisms that live in water totally independent of soil as a resource? Answer: Almost all living organisms are dependent on soil. Some depend directly, while some depend indirectly.

Plants need soil for getting support as well as nutrients to prepare their food. On the other hand, organisms depend on plants for food and other substances that are essential for life. Herbivores depend directly upon plants, and carnivores depend upon animals, which in turn depend upon plants for food. This makes them depend on soil indirectly.

Organisms that live in water are not totally independent of soil as a resource. These organisms depend on aquatic plants for food and other substances. These aquatic plants in turn require minerals for their sustenance. These minerals are carried to water bodies from soil by rivers, rainwater, etc. Without the supply of minerals from the soil to the water bodies, it is impossible to imagine aquatic life.

Question 4. You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather? Answer: The meteorological department of the government collects data on the elements of weather such as maximum and minimum temperatures, maximum and minimum humidity, rainfall, wind speed, etc. They are able to study these elements using various instruments. The maximum and minimum temperature of a day is measured by a thermometer known as the maximum-minimum thermometer. Rainfall is measured by an instrument known as the rain gauge. Wind speed is measured by anemometers. There are various instruments used to measure humidity.

Question 5. We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soiL Do you think that isolating these activities to specific and limited areas would help in reducing pollution? Answer: Yes. Isolating human activities to specific areas would help in reducing levels of pollution. For example, setting up of industries in isolated regions will control pollution to some extent. The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.

Question 6. Write a note on how forests influence the quality of our air, soil and water resources. Answer: Forests influence the quality of our air, soil, and water resources in various ways. Some of them are:

• Forests balance the percentages of carbon dioxide and oxygen in the atmosphere. The increasing amount of carbon dioxide caused by human activities is balanced by a larger intake of carbon dioxide by plants during the process of photosynthesis. Simultaneously, a large amount of oxygen is released.
• Forests prevent soil erosion. Roots of plants bind the soil tightly in a way that the surface of the soil cannot be eroded away by wind, water, etc.
• Forests help in the replenishment of water resources. During the process of transpiration, a huge amount of water vapour goes into the air and condenses to form clouds. (These clouds cause rainfall that recharge water bodies.

Class 9 Science Chapter 14 Natural Resources Additional Important Questions and Answers

Choose the correct option:

Question 1. The atmosphere of the earth is heated by radiations which are mainly (a) radiated by the sun (b) re-radiated by land (c) re-radiated by water (d) re-radiated by land and water Answer: (d) re-radiated by land and water

Question 2. If there were no atmosphere around the earth, the temperature of the earth will (a) increase (b) go on decreasing (c) increase during day and decrease during night (d) be unaffected Answer: (c) increase during day and decrease during night

Question 3. What would happen, if all the oxygen present in the environment is converted to ozone? (a) We will be protected more (b) It will become poisonous and kill living forms (c) Ozone is not stable, hence it will be toxic (d) It will help harmful sun radiations to reach earth and damage many life forms. Answer: (b) It will become poisonous and kill living forms

Question 4. One of the following factors does not lead to soil formation in nature (a) the sun (b) water (c) wind (d) polythene bags Answer: (d) polythene bags

Question 5. The two forms of oxygen found in the atmosphere are (a) water and ozone (b) water and oxygen (c) ozone and oxygen (d) water and carbon-dioxide Answer: (c) ozone and oxygen

Question 6. The process of nitrogen-fixation by bac¬teria does not take place in the presence of (a) molecular form of hydrogen (b) elemental form of oxygen (c) water (d) elemental form of nitrogen Answer: (b) elemental form of oxygen

Question 7. Rainfall patterns depend on (a) the underground water table (b) the number of water bodies man area (c) the density pattern of human population in an area (d) the prevailing season in an area Answer: (b) the number of water bodies man area

Question 8. Among the given options, which one is not correct for the use of large amount of fertilisers and pesticides? (a) They are eco-friendly (b) They turn the fields barren after some time (c) They adversely affect the useful component from the soil (d) They destroy the soil fertility Answer: (a) They are eco-friendly

Question 9. The nitrogen molecules present in air can be converted into nitrates and nitrites by (a) a biological process of nitrogen fixing bacteria present in Soil (b) a biological process of carbon fixing factor present in soil (c) any of the industries manufacturing nitrogenous compounds (d) the plants used as cereal crops in field Answer: (a) a biological process of nitrogen fixing bacteria present in Soil

Question 10. One of the following processes is not a step involved in the water-cycle operating in nature (a) evaporation (b) transpiration (c) precipitation (d) photosynthesis Answer: (d) photosynthesis

Question 11. The term “water-pollution” can be defined in several ways. Which of the following statements does not give the correct definition? (a) The addition of undesirable substances to water-bodies (b) The removal of desirable substances from water-bodies (c) A change in pressure of the water bodies (d) A change in temperature of the water bodies Answer: (c) A change in pressure of the water bodies

Question 12. Which of the following is not a greenhouse gas? (a) Methane (b) Carbon dioxide (c) Carbon monoxide (d) Ammonia Answer: (d) Ammonia

Question 13. Which step is not involved in the carbon-cyicle? (a) Photosynthesis (b) Transpiration (c) Respiration (d) Burning of fossil fuels Answer: (b) Transpiration

Question 14. ‘Ozone-hole’ means (a) a large sized hole in the ozone layer (b) thinning of the ozone layer (c) small holes scattered in the ozone layer (d) thickening of ozone in the ozone layer Answer: (b) thinning of the ozone layer

Question 15. Ozone-layer is getting depleted because of (a) excessive use of automobiles (b) excessive formation of industrial units (c) excessive use of man-made compounds containing both fluorine and chlorine (d) excessive deforestation. Answer: (c) excessive use of man-made compounds containing both fluorine and chlorine

Question 16. Which of the following is a recently originated problem of environment? (a) Ozone layer depletion (b) Greenhouse effect (c) Global warming (d) All of the above

Very Short Answer Questions

Question 1. Define the term natural resource. Answer: Any useful material obtained from the nature is called a natural resource.

Question 2. What are two types of natural resources? Answer: The two types of natural resources are renewable resources and non-renewable resources.

Question 3. Which zone of atmosphere is the closet to the earth? Answer: Troposphere

Question 4. Name the three important constituents of the air. Answer: The three important constituents of soil are nitrogen, oxygen and carbon dioxide.

Question 5. Where on earth the British researchers have found the ozone hole in 1985? Answer: Over South Antarctica.

Question 6. Montreal protocol in 1986 had banned on the emission of a pollutant to protect the ozone layer. Name the pollutant. Answer: Montreal protocol had banned the emission of CFCs (Chlorofluro carbon)

Question 7. Name some of the greenhouse gases. Answer: Carbon dioxide, methane, sulphur dioxide and CFCs.

Question 8. Which two types of components are found in biosphere? Answer: Biotic (living) components and abiotic (Non-living) components.

Question 9. List the factors which contribute to the weathering of rocks in soil formation. Answer: The factors are temperature, air, water and living organisms like lichens.

Question 10. Which factor is responsible for deciding the type of soil? Answer: The average particle size decides the type of soil.

Question 11. Which type of soil causes early waterlogging conditions? Answer: Clayey soil

Question 12. Why is there a need to conserve the natural resources? Answer: The conservation of natural resources is essential for the sustainable development.

Question 13. What is biosphere? Answer: The life supporting zone, of the earth where the lithosphere, hydrosphere and atmosphere interact is called biosphere.

Question 14. What do you understand by top soil? Answer: The top soil is the uppermost layer of soil that contains humus and living organisms in addition to soil particles. It also holds the plants.

Question 15. Name the three forms of nitrogen fixation. Answer: The three forms of nitrogen fixation are atmospheric fixation, biological fixation and industrial fixation.

Short Answer Questions

Question 1. What is atmosphere? State its importance to life on the earth. Answer: A thick blanket of air present around the earth is called atmosphere. It is a bad conductor of heat as during day time, the atmospheric gases prevents excessive rise in surface temperature of the earth for the survival of life and at night time the same gases prevent the escape of heat from earth surface to keep it warm.

The air present in atmosphere also contains life supporting gases such as oxygen and carbon dioxide.

Question 2. Mention the different constituents of the soil. Answer: The different constituents of soil are

• Powdered rock particles formed after the weathering of rocks.
• Micro-organisms included in the decomposition of organic matter.
• Water droplets
• Organisms like earthworm for whom the top soil acts as their habitat.

Question 3. Why is soil important for plants? Answer: Soil is important to plants because it is a source of

• water required by the plants.
• mineral nutrients required by the plants
• support required by plants to stand erect even in windy or stormy conditions.

Question 4. What is soil pollution? Answer: The removal of useful components of soil and the addition of other substances which interfere with the soil fertility and harm the diversity of microorganisms present in soil is called soil pollution. The application of chemical fertilizers, pesticides and addition of domestic and industrial waste to soil, along with increased degree of soil erosion are the major causes of soil pollution.

Question 5. Differentiate in water table and water depth. Answer: The minimum depth fo soil where all pore spaces in soil are filled with water make up the water table. Thus, the upper level zone of saturation is called water table.The depth of water level is expressed with reference to mean sea level.

The vertical distance from place on the surface of the earth to the water table is called the water level.

Question 6. Differentiate in the two types of components found in the biosphere. Answer: The types of the components found in the biosphere are biotic and abiotic components. The biotic components include all living organisms from microorganisms to higher plants and animals. The abiotic components include all non-living components such as air, water and soil.

Question 7. Why do we need to conserve the natural resources? Answer: The conservation of natural resources means their wise and judicious use. It is essential to conserve the different natural resources to ensure

• The availability of natural resources for a longer time.
• The maintenance of the quality of the natural resources.
• To achieve the sustainable development.

Question 8. List two ways in which carbon dioxide is fixed in nature. Answer: The carbon dioxide is fixed in nature by

• Green plants who produce sugar by the reduction of carbon dioxide in photosynthesis.
• Aquatic mostly marine animals molluscs who use carbonates present in seawater to make their protective shell

Question 9. Mention some of the pollutants of air. Answer: Any undesirable substance added to air that causes the decline in the quality of air is called air pollutant. The different air pollutants include:

• Oxides of sulphur such as SO 2 and SO 3 .
• Oxides of nitrogen such as NO and NO 2
• Greenhouse gases such as methane and carbon dioxide
• Unburnt particles of carbon called soot.
• Carbon monoxide
• Dust and smoke

Question 10. What is smog? Answer: The presence of oxides of sulphur, oxides of nitrogen, greenhouse gases such as methane and carbon dioxide, unburnt particles of carbon, dust and smoke in air mixes with fog to form smog in cold weather conditions. The smog formation reduces the visibility that harms the productivity because of the delay in travelling times, corrosion of metallic and marble structures.

Question 11. Describe ozone as a chemical weed. Answer: Ozone is considered as a chemical weed because when on earth surface as a bluish gas, it is toxic to life but high up in stratosphere, it protects the life from the UV-rays present in solar radiations. The UV rays have harmful effects on human life because they are considered responsible for

• Increasing incidences of skin bums and skin cancer.
• Increasing cases of cataract.
• Reducing crop production by more than 20%.

Question 12. Which chemicals have reduced the thickness of ozone layer in stratosphere? Answer: Man made compounds called CFCs (Chlorofluro carbons) are very stable compounds. These compounds released from refrigerators and air conditioners cannot be degraded by any biological process. When they reach the ozone layer, the chlorine present in them combines with the monatomic oxygen produced on the dissociation of ozone to form stable compound. This continuously occurring reaction causes fire depletion of ozone layer.

Nitric oxide (NO) released in air also contributes to the depletion of the ozone layer.

Long Answer Questions

Question 1. How the two biological processes respiration and photosynthesis are interrelated? Give an example to support your answer. Answer: The two biological processes, photosynthesis and respiration are interrelated because the end products of cellular respiration i.e. carbon dioxide and water are the raw materials in the process of photosynthesis and the end products of photosynthesis i.e. sugar and oxygen are the raw materials used in the process of cellular respiration. Respiration, C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + Energy Photosynthesis, 6CO 2 + 12H 2 O + Solar energy → C 6 H 12 O 6 + 6H 2 O + 6O 2

Therefore, in green plants during early morning and later evening, no gaseous exchange takes place as at this time, rate of photosynthesis equals the rate of respiration taking place in their cells.

Question 2. Explain the water cycle with the help of a diagram. Answer: The water cycle involves

• the evaporation of water in form of its vapours from the earth surface and hydrosphere under the heating effect of solar radiations.
• the condensation of water vapours high up in atmosphere to form clouds containing water in its condensed form of water droplets.
• the precipitation that returns the water back to earth in form of rain, hail or snow.

Question 3. Draw and explain nitrogen cycle in nature. Answer: Nitrogen is almost chemically inert gas but is the major constituent of the atmospheric air. (78%) It cannot be directly used by the plants and animals but is essential for all living organisms being the major constituent of proteins and nucleic acids. Therefore, the atmospheric nitrogen is first fixed in form of compounds that can easily be absorbed by the plants.

In nature nitrogen fixation occurs in three possible ways. These are

• Atmospheric fixation, when lightning occurs during thunder storm. The nitrogen combines with oxygen to form its oxide or nitrogen combines with hydrogen to form ammonia. These oxides being water soluble reach the earth with rainwater.
• Biological fixation which is carried out by the free nitrogen fixing cyanobacteria like nostoc and anabena or by the bacteria named Rhizobium present in the root nod-ules of legume plants.
• Industrial fixation involves the formation of nitrogen compounds by chemical fertilizer producing companies.

The nitrogen compounds present in soil in form of nitrites undergo nitrification by bacterial action to form nitrate ions that are absorbed by the plants and used up in synthesis of proteins and nucleic acids. From plants, the nitrogen compounds reach animals in form of amino acids and nitrogenous bases for their growth.

Question 4. How is carbon cycle completed in nature? Answer: Carbon is incorporated into plants by process of photosynthesis. The process converts the gaseous carbon dioxide present in atmosphere or dissolved in water into glucose molecules. These molecules are the source of energy after their oxidation in the process of respiration. The process involves the release of carbon dioxide back in the atmosphere.

The compounds of carbon in different forms of carbohydrates, proteins and fats passes into animals for their survival.

The process of combustion of fuels also adds carbon dioxide to the atmosphere. The combustion involves the oxidation of compounds of carbon or carbon alone to produce energy in the form of heat and light. A small percentage of carbon in gaseous state is also released on the decomposition of organic matter by decomposers. A small percentage of carbon dioxide dissolved in water is also involved in formation of carbonates that are used by aquatic animals to make shells.

Question 5. Explain the oxygen cycle in nature. Answer: Oxygen gas is very important for most of the living organisms and is also abundantly available in atmospheric air, 21% by volume of the total atmospheric air. It is also present in form of its compounds in lithosphere such as metallic oxides and form of oxides of carbon, sulphur and nitrogen in air. In living organisms, it is the major constituents of essential organic compounds like carbohydrates, fats, etc.

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Important Questions for CBSE Class 9 Science Chapter 14 - Natural Resources

• Class 9 Important Question
• Chapter 14: Natural Resources

CBSE Class 9 Science Chapter-14 Important Questions - Free PDF Download

The important questions of Natural Resources Class 9 will help the students to understand the topics covered in this chapter in-depth and prepare for their examination in an orderly manner. Class 9 Science Ch 14 extra questions or important questions are written in a simple and easy-to-understand language by the subject-matter experts at Vedantu. To get a fair idea about the subject, students can rely on Class 9 Chapter 14 Important questions PDF. Students can download the Important Questions of Class 9 Science Chapter 14 PDF for free from Vedantu, and study even when they are offline. Vedantu is a platform that provides free CBSE Solutions (NCERT) and other study materials for students. Maths Students who are looking for better solutions can download Class 9 Maths NCERT Solutions to help you to revise the complete syllabus and score more marks in your examinations.

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Study Important Questions for Class 9 Science Chapter 14 – Natural Resources

1 Marks Questions 

1. Which of the following does not contribute to the biotic components of the biosphere?

Decomposers

Ans: d) Air

2. Which of the following is the major source of minerals in the soil?

Parent rock from which soil is covered 

Plants 

Animals 

Ans: a) Parent rock from which soil is covered.

3. Which of the following factors does not cause soil formation in nature?

Polythene bags

Ans: c) Polythene bags

4. The conversion of atmospheric nitrogen into nitrites and nitrates compounds can be occured by

The process of nitrogen fixation by the bacteria present in soil.

The process of carbon fixation by carbon fixing factors present in soil. 

Any of the industries manufacturing nitrogenous compounds. 

The plants used as cereal crops in the field.

Ans: a) The process of nitrogen fixation by the bacteria present in soil.

5. Write down two forms of oxygen found in the atmosphere.

Ans: Ozone and Oxygen.

6. Write names of two compounds that contain both nitrogen and oxygen and are biologically important.

Ans: Proteins and urea are biologically important compounds that contain both nitrogen and oxygen.

7. Which of the given options is not fossil fuel?

Ans: c) Wood.

8. Carbon cycle does not have which of the following steps?

Respiration

Transpiration

Photosynthesis

Burning of fossils

Ans: b) Transpiration.

9. How much of the earth's surface is covered with water?

Ans: d) 85%

10. On barren rocks, lichens grow after the growth of which of the following organisms?

Gymnosperms

Ans: a) Mosses.

11. How will the earth’s temperature change, if there will be no atmosphere?

Earth’s temperature will decrease in that case.

Earth’s temperature will increase in that case.

Earth’s temperature will be unaffected in the absence of atmosphere.

Earth’s temperature will increase in daytime and will decrease at night.

Ans: d)  Earth’s temperature will increase in daytime and will decrease at night.

12. Soil fertility decreases due to which of the following factors?

Crop rotation

Soil erosion

Afforestation

Strip cropping

Ans: b) Soil erosion.

13. Which of the following organisms cannot fix nitrogen in the atmosphere?

Azotobacter

Ans: c)  E. Coli

14. Which atmospheric gas absorbs the harmful UV radiations coming from the sun?

Ans: d) O 3 (Ozone)

15. Ozone layer depletion is caused by _____.

Ans: c) CFC’s

16. Which of the following statements is not correctly related to the ‘Water Pollution’?

Undesirable substances are added to the water bodies.

Undesirable substances are removed from the water bodies.

Pressure change in water sources.

Temperature change in water sources.

Ans: c) Pressure change in water sources.

17. The pattern of rainfall depends on which of the following factors?

Water table present underground

Number of natural water sources present in a zone

Population density of humans in an area

Prevailing season in an area.

Ans: b)  Number of natural water sources present in a zone.

18. The air present on Venus and Mars has which of the following components?

Ans: a) CO 2

19. Which of the following gases is present in a high amount in the atmosphere?

Carbon dioxide

Ans: c) Nitrogen

20. From outside to inside, the sequence of regions of earth are ____.

Core, mantle, and crust 

Core, crust, and mantle 

Crust, mental, and core 

Mantle, core, and crust

Ans: c) Crust, mental, and core.

21. _____ is the topmost layer of earth’s surface.

Troposphere 

Stratosphere 

Mesosphere 

Thermosphere 

Ans: (d) Thermosphere

22. Which of the following processes convert O 2 to CO 2 ?

Photosynthesis 

Breathing 

Respiration 

Both (a) and (b) 

Ans: c) Respiration

23. Define the atmosphere and name the different regions of the atmosphere.

Ans: The atmosphere is the layer of air that surrounds the earth. Following are the different regions of the atmosphere:

(a) Troposphere 

(b) Stratosphere 

(c) Mesosphere 

(d) Thermosphere

25. The process of conversion of water vapor into water droplets is known as ____.

Condensation

Sublimation

Evaporation

Ans: a) Condensation

26. The process of evaporation of plant water through its leaf surface is _____.

Both a) and c)

Ans: b) Transpiration

27. What is the %age of O 2  in the air?

12.5% 

Ans: a) 21%

28. What is the full form of CFC?

Carbon fluorine compounds 

Carbon fluoro compound 

Chloro fluoro carbons 

Chlorine fluoro compound 

Ans: c) Chloro fluoro carbons 

29. From the given options, greenhouse gas is ____.

Both a) and b)

Ans: b) Carbon dioxide

30. On which layer of earth, is life possible?

Biosphere 

Lithosphere 

Hydrosphere 

None of the above

Ans: a) Biosphere

31. Which of the following is the major component of the atmosphere of Mars?

Ans: c) Carbon dioxide

2 Marks Questions

1. During the water cycle, water is found in how many states?

Ans: Water is present in all three states of matter during the water cycle which are ice (solid form), water (liquid form), and water vapor (gaseous form).

2. Write any three human activities that can lead to an increase in the amount of carbon dioxide in the air. 

Ans: Human activities that can increase the content of carbon dioxide in the air are given below:

Combustion of coal and oil 

Burning wood 

Deforestation (deforestation).

3. Define the greenhouse effect.

Ans: The phenomenon in which the temperature of the earth rises due to the trapping of harmful radiations by greenhouse gases such as carbon dioxide and methane that result in global warming is called the greenhouse effect.

5. Define soil erosion.

Ans: The process of wearing away topsoil that is rich in humus is known as soil erosion.

6. What role do the decomposers play in the biogeochemical cycle? 

Ans: The decomposer breaks down rotten and dead organic matter into simpler forms and returns back the minerals to nutrient pools such as air, water, and soil.

7. Define the greenhouse effect. Write down the name of any one greenhouse gas. 

Ans: The phenomenon of an increase in global temperature due to an increase in the concentration of carbon dioxide gas in the atmosphere is known as the greenhouse effect. 

Carbon dioxide is one of the major greenhouse gases.

8. Mention some methods by which soil erosion can be prevented.

Ans: Methods to prevent soil erosion are given below:

Stop deforestation and plant more trees.

The borders of the crop fields should be planted with a few trees to mitigate the effects of strong winds on the fields. 

Crop rotation i.e. growing different types of crops in the same field in a sequential manner should be applied to maintain soil fertility. The water retention capacity of the soil is also maintained in this way.

9. Write some causes of Water Pollution.

Ans: Water pollution can be caused by: - 

a) Household waste such as detergent or sewage. 

b) Agricultural wastes like fertilizers and pesticides are used for better crop production. 

c) Calcium and magnesium compounds get dissolved in water and also act as pollutants in natural sediments. 

d) Rivers, ponds, lakes, and other water bodies are used for bathing or washing purposes which results in water pollution as well as contaminate the water with a variety of bacteria and protozoa.

10. Mention the different types of natural resources with examples.

Ans: There are two types of natural resources which are given below:

a) Inexhaustible natural resources - There are some resources which are present in unlimited numbers in nature and are unlikely to be depleted by normal human activity like solar energy, air, water, etc.

b) Exhaustible Natural Resources - These resources exist in limited quantities in the natural world and may be depleted by human activities if not used in limits like coal, petroleum, and minerals.

11. Write some differences between renewable and non-renewable resources.

Ans: Some of the differences between renewable and nonrenewable resources are given below:

12. Discuss how the rivers add minerals, taken from land to the seawater?

Ans: The river passes over land, absorbs the minerals present in the soil and adds them to the sea.

13. Draw a diagram representing the water cycle.

Ans: The following diagram represents the water cycle:

(Image will be uploaded soon)

14. Write down any two methods to restore the fertility of soil.

Ans: Soil fertility can be restored using the following methods: 

 (a) Alternately cultivate beans and other types of crops. 

 (b) Using manure and fertilizer.

15. Why does growing legumes increase soil fertility? 

Ans: Legumes have nodules in their roots. There are nitrogen-fixing bacteria present in the nodules of these leguminous plants, which convert atmospheric nitrogen into soluble compounds. By adding these compounds to the soil, soil fertility increases.

16. Write any two reasons, mentioning over-exploitation of natural resources. 

Ans: Over-exploitation of natural resources is caused by: 

(a) Significant increase in population 

(b) Advances in industry and technology are the major reasons for the increase in the use of resources. 

(c) Rapid increase in urbanization.

17. Write down the constituents of soil.

Ans: Soil has the components given below: 

(a) It contains soil particles like gravel, sand, silt and clay. 

(b) It has humus which is formed by the decomposition of dead organisms and organic matter.

(c) Soil water 

(d) Soil air

(e) Soil organisms like bacteria, earthworms, etc.

18. Define soil. How is it important for humans? 

 Ans: Soil is the top fertile layer of the earth called soil. It provides us - 

 (i) Soil provides food and feed. 

 (ii) It provides material for clothes.

 (iii) It provides anchorage to plants. 

 (iv) It provides water and minerals in plants.

19. What is the importance of air?

Ans: Following are the importance of air:

a) Air provides oxygen gas for respiration in animals and plants. 

b) Air provides CO 2 for photosynthesis. 

c) The atmosphere affects the climate by squeezing the sun's rays that reach the earth. 

d) Air is a repository of some life-critical elements.

20. Write down the factors that affect soil fertility. 

Ans: Soil fertility depends on 

The presence of organic matter (humus) and nutrients.

Soil capacity to retain water and air.

21. Describe biological nitrogen fixation. Specify the name of the organism responsible for it. 

Ans: The process by which nitrogen in the atmosphere is converted  into a soluble and usable form by microorganisms is called nitrogen-fixation. Microorganisms responsible for nitrogen fixation include Rhizobium, Azotobacter, and Blue green algae.

22. Define biogeochemical cycle.

Ans: Biogeochemical cycle is the constant interaction between biotic and abiotic components of the biosphere that causes the exchange of matter and energy between them.

23. What are the reasons behind the possibility of life on the earth?

Ans: Life on earth is possible because: 

 (a) Earth temperatures are suitable for a variety of life forms. 

 (b) Oxygen is present in the air that is required by all living things.

24. What is the requirement of freshwater by terrestrial life forms? 

Ans: Creatures that live on land need freshwater because their bodies cannot withstand saline water and also they cannot excrete the high amount of dissolved salt in seawater.

25. How is the climate-controlled by the atmosphere? 

Ans: During the day, the atmosphere keeps the earth's average temperature constant and also prevents rapid temperature rise during the day. It also prevents heat from escaping into outer space, in this way, maintains a survivable climate on earth.

26. What is the process by which winds are created?

Ans: The air over land quickly heats up and begins to rise in the daytime. As it rises, it creates a zone of low pressure and the air moves from the sea towards the low pressure zone. The movement of this air from one area to another creates wind.

27. How does the sun help to break down the rocks into smaller pieces to form soil? 

Ans: The sun heats and expands up the rock during the day. At night, this rock cools and shrinks. Because not all parts of the rock expand and contract at the same rate, as a result massive cracks form and then they break into smaller pieces.

28. What is the composition of air?

Ans: The air has following components:

In addition to the gases, water vapors are also present in the air.

29. How does soil pollution occur?

Ans: Soil pollution occurs in the following ways: 

Using high amounts of fertilizers and pesticides kill the microorganisms that help to recycle the nutrients from the soil. 

Earthworms that created humus and fertilized the soil are also getting killed with increased use of pesticides.

Addition of harmful substances and removal of useful components also affect the soil fertility.

30. Describe the carbon cycle that occurs in nature.

Ans: Following are the processes involved in the carbon cycle:

(a) Plants convert the atmospheric carbon dioxide into organic compounds which then go to the animals when eaten by the animals. 

(b) Plant organic compounds are also converted into petroleum and coal. 

(c) Carbon dioxide is converted directly into carbonic acid or carbonates when present in water and then switched to the limestone. 

(d) Organic compounds of animals change into carbon dioxide in the atmosphere by respiration and decomposition process.

Diagram Representing Carbon Cycle

1. Define smog and the process of its formation.

Ans: Smog - Smog is the combination of smoke and fog.

Formation of smog - Smog is formed when air pollution exists and a high level of smoke is formed in the atmosphere. This smoke gets mixed with the fog and forms smog.

2. What is the importance of water in life?

Ans: Water is important for life because:

All types of life processes occurring inside the cell take place in a water medium.

Transportation of various substances in the body occurs through the water.

Transportation of various substances in plants also occurs through the water.

3. How do living things cause the erosion of rocks? 

Ans: Organisms such as lichens when growing on the surface of a rock, release certain chemical substances that cause crushing of the surface of the rock, breaking it down into fine particles.

4. What is the process of rain formation? 

Ans: Water vapors are formed when water from the water bodies evaporates. These water vapors move up in the atmosphere and condense to form small water droplets. When a huge amount of water droplets are collected, it becomes a large water droplet and becomes heavy which results in the falling of rain.

5. Explain the oxygen cycle that occurs in the atmosphere.

Ans: The following processes occur in the oxygen cycle:

Animals and humans take up the oxygen present in the air for respiration.

They produce water and carbon dioxide as the byproduct of respiration and release them out of their body.

These byproducts are used by plants during photosynthesis.

Plants make organic compounds as well as release oxygen gas in air after using the byproducts of respiration (water and carbon dioxide) by animals.

Oxygen is restored in the atmosphere and glucose is used by plants and animals.

3 Marks Questions

1. How is the earth’s atmosphere different from that of Venus and Mars? 

Ans: The air present on the earth is mainly a mixture of many gases like nitrogen (78%), oxygen (21%), and carbon dioxide (0.03%). However, on planets such as Venus and Mars, it has been observed that carbon dioxide is the major component of their atmospheric air. It has been found that carbon dioxide is 95-97% in the atmosphere of Venus and Mars.

2. Why is the atmosphere considered a blanket? 

Ans: Because air is a bad conductor of heat, the atmosphere that covers the earth is like a blanket. The atmosphere significantly stabilizes the earth's average temperature during the day and even throughout the year. The atmosphere prevents rapid temperature rises during the day and also it slows the rate at which heat goes out into space at night time.

3. How is the wind created? 

Ans: Due to the heated land or water, the air present over their surface also gets heated up and rises. The air present over land gets rapidly heated up as compared to the air present over water because land gets heated faster than the water. Hence, the air on land heats up faster during daytime and begins to rise. When this air rises, a low-pressure region is created and the air above the sea moves to the low-pressure region. The wind is created due to the movement of air from one region to another.

4. What is the process of cloud formation?

Ans: A large amount of water evaporates and moves to the air when the water bodies get heated up during the day. Other biological activities also cause the movement of water in the atmosphere. Along with the water vapors, the air also gets heated up and rises. When the air rises, it expands and cools. The cooling causes condensation of the water vapors and converts them into droplets. This condensation of water is facilitated when some particles are able to act as the "nucleus" around which these droplets can form. In general, dust in the air and other suspended particles act as nuclei. Clouds are formed by this process.

5. Write down the human activities that are responsible for causing air pollution.

Ans: The given human activities can cause air pollution:

Combustion of fossil fuels such as coal or petroleum releases various nitrogen oxides and sulfur oxides into the air.

Smoke and other suspended particles are released into the air due to burning of wood.

Usage of harmful chemicals like aerosols, CFCs, etc can cause air pollution.

6. What is the need for water for living organisms?

Ans: Living organisms require water to perform various life processes. All living things are made up of cells and all types of cellular processes take place in water medium. The chemical reactions take place in living cells between the compounds that are dissolved in water. Also transportation of various substances occurs from one part of the body to another in dissolved form. Therefore, to stay alive, living organisms require to maintain the water level in their bodies.

7. What are the freshwater sources in different places on earth?

Ans: Following are some freshwater sources found in different places on earth:

Wells and Tubewells

Rainwater provides water to all of the above freshwater sources.

8. Do you know about activities that can pollute the freshwater sources? 

Ans: We use fertilizers and pesticides in our farms. Their excess use can pollute these water sources. The sewage in our towns and cities and waste from factories and water used for cooling in a variety of operations in certain industries well are released into these water sources. Such activities pollute water bodies.

9. What is the process of soil formation?

Ans: Over a long period of time, like millions of  years ago, the rocks present on earth were weathered by various physical, chemical and biological factors. This weathering resulted in the formation of soil particles. The factors responsible for weathering of rocks and formation of soil are given below:

The Sun: The heat radiation of the sun causes the expansion of rocks. These rocks cool down at night and contract, thus, forming cracks in the rocks.

Water: Water supports two methods by which soil formation takes place. First, water can enter cracks of rock formed due to uneven heating by the sun. And later on this water freezes and causes cracks to spread.

Wind: Strong winds rub against rocks and erode them down in a similar way to that of water.

Living organisms: Some living organisms release chemicals that cause crushing of the rocks. Lichens are such organisms that grow on the rocks and release some chemicals that convert the rocks into soil particles. Some other plants like mosses grow on rocks and create cracks in the rocks as their roots penetrate into the rocks.

10. By which methods soil erosion can be reduced or prevented?

Ans: By applying the following methods, soil erosion can be reduced or prevented:

Deforestation and overgrazing of animals should be reduced.

More trees should be planted to support afforestation or reforestation.

Agricultural methods should be improved.

11. What is the role of the atmosphere to make life possible on earth?

Ans: The atmosphere is essential for life in the following ways:

It protects the living organisms from harmful sun radiations by acting like a blanket that covers the earth’s surface and traps the harmful UV radiations from the sun. In this way, the atmosphere also maintains a constant temperature of the earth.

Carbon dioxide for photosynthesis and oxygen for respiration and combustion is provided by the atmosphere.

A sudden change in the earth’s temperature is prevented by the atmosphere.

12. What is the role of water to make life possible on earth?

Ans: Water is essential for all types of life forms because:

All living organisms comprise living cells and all types of cellular processes occur in water medium. All types of metabolic reactions occur in living organisms and in their cells take place between the substances that are dissolved in water.

Transportation of substances that occur in living organisms take place in dissolved form.

Water is required in digestion, excretion, and egestion-like body processes.

Water regulates the body temperature of organisms by sweating and evaporation.

13. How do living things depend on the soil? Are the organisms living in the water completely independent of the soil as a resource? 

Ans: Plants require simple nutrients, such as certain elements to grow normally, and most of these elements are obtained from the soil. Plants use these elements to prepare their own food in the presence of the sun. Because all other living things depend on plants for their development and diet, we can say that organisms living in water are not completely independent of soil as a resource. Another reason is that the organic matter in the soil is dissolved in the water to provide nutrients for aquatic organisms.

14. There are weather reports on television and in newspapers. How predictable are these weather reports?

Ans: The weather forecast is based on information gathered from general patterns of temperature, humidity, wind and cloud changes.

15. There are many human activities that lead to increased air, water, and soil pollution. Do you think that isolating these activities in restricted and enclosed areas will help to reduce pollution?

Ans: Isolating many human activities that cause an increase in air, water, and soil pollution will help reduce water and soil pollution, but it is unlikely to affect the severity of air pollution, because gases can spread easily from the transmission area to other places nearby. We need to focus on the sustainable management of  resources, rather than isolate them, and reduce or replace their consumption, such as using clean fuels such as CNG to replace fossil fuels.

16. Explain how forests affect the quality of air, water, and soil resources.

Ans: Effects of forests on air: Trees and plants in the forest can absorb carbon dioxide and release oxygen, thereby maintaining the level of these gases in the biosphere.

Effects of forests on water: Forests enable the water cycle in nature to form clouds and condense to cause rainfall.

Effects of forests on soil: The roots capture soil particles and prevent soil erosion. Dead trees and plants or parts of them enrich the soil with humus and organic matter, making it fertile.

17. Write down the biotic and abiotic factors that cause soil formation.

Ans: Some of the abiotic factors that cause soil formation are given below:

Biotic factors responsible for soil formation:

Some living organisms release chemicals that cause crushing of the rocks. Lichens are organisms that grow on the rocks and release some chemicals that convert the rocks into soil particles. Some other plants like mosses grow on rocks and create cracks in the rocks as their roots penetrate into the rocks. 

18. Mention down some sources that cause air pollution.

Ans: The given sources can cause air pollution:

Air pollution can be caused by some natural processes like forest fires, smoking volcanoes, sandstorms, floating pollen particles, and organic degradation.

Consequences of some human activities like overpopulation, deforestation, urbanization and industrialization.  

The burning of fossil fuels in automobiles, thermal power stations and industries cause air pollution.

19. Why is the Mathura refinery a problem for the Taj Mahal?  

Ans: The Mathura refinery emits acidic gases such as sulfur dioxide and nitrogen dioxide into the air. In the presence of moisture, sulfur dioxide is oxidized to sulfuric acid, and nitrogen dioxide is oxidized to nitric acid in the air. Acid reaches the surface and water bodies together with rain. Acid rain is rainwater that contains acid as a pollutant. This acid rain caused problems for Taj Mahal marble.

20. How does the atmosphere function as a protective blanket? Did you mention the harmful effects of ultraviolet light?  

Ans: The atmosphere protects the earth as it absorbs most of the harmful radiation, such as ultraviolet radiation from the sun. The harmful radiation is absorbed by the upper atmosphere and reflected back to space. The sun's rays are reflected back to space by dust particles, water vapor, and clouds. Because of this, the earth receives the necessary heat and light from the sun, which helps control the weather and allows living things to survive.  The harmful effects of UV radiation cause blindness and skin cancer.

21. Explain the reasons:  

a) Step farming is very common in the mountains.   

Ans: (a) On hilly slopes, step farming reduces the steepness of the slope, and thus controls soil erosion.  

b) Fertile soil contains a lot of humus. 

Ans: The decomposition of dead organic matter occurs in the topsoil. This monastery, built-in , converts organic materials into humus. Therefore, fertile soil has humus.

22. What are the hazards of air pollution?  

Ans: The Harmful Effects of Air Pollution are:

Air pollution affects the respiratory tract of living things, causing bronchitis,  pneumonia, asthma, and lung cancer.  

The burning of fossil fuels such as coal and patrols releases nitrogen oxides and sulfur, and  causes acid rain.  

Burning fossil fuels such as coal and petroleum will also increase particulate matter in the air. The presence of these pollutants in the air during the cold season can cause the formation of smog, which reduces visibility and causes road problems.

23. Most of the land is surrounded by the sea. Then why do we need to save water?  Ans: Maintaining water conservation: 

Due to population growth, water consumption is increasing substantially.  

Due to increased water pollution.  

The water level is falling due to the decrease in precipitation.

24. What is weathering? How does weathering happen?  

Ans: The formation of soil due to the destruction of rocks is called weathering.  is derived from  

physical factors such as the sun (temperature), rain, wind, and frost.  

Biological media-through the action of plants, animals and microorganisms.

25. Write down how to increase the concentration of carbon dioxide in the atmosphere.

Ans: By following ways, the concentration of carbon dioxide increases in the atmosphere:

Both plants and animals emit carbon dioxide into the atmosphere through respiration.  

When organic waste and carcasses are decomposed by decomposers.  

Burning fossil fuels such as wood, coal, gasoline, natural gas and kerosene.  

By volcanic eruptions.  

The carbonate rock is weathered by soil microorganisms, plant roots and acid rain.

26. "Water is important." Give the reason for the statement.  

Ans: The value of the water of life is  explained in the following points:

It acts as a universal solvent.  

Most of the activities in the body are carried out in the water.  

The transfer of a substance from one part of the body to another in a dissolved form.

Dissolve waste and promote excretion from the body.  

Aquatic organisms use oxygen dissolved in water.

27. How do forests affect our air, water, and soil? 

Ans: Forests affect air, water, and soil in the following ways:

The forest acts as an air purifier. During photosynthesis, they consume carbon dioxide and release oxygen.  

 The forest also keeps the water level below ground level. The roots absorb water and raise the water level. Trees also contribute to cloud formation during evaporation and increase the humidity (water vapor) in the air. This water vapor will form more clouds, which will help when it rains. 

Tree roots support the soil and prevent erosion, thereby maintaining soil fertility.

28. What is the greenhouse effect? How does this affect the earth’s atmosphere?

Ans: An increase in the concentration of watr vapor and other atmospheric gases (such as nitrous oxide methane) will prevent the release of solar radiation. This increases the temperature of the atmosphere above the earth's surface, making it warmer. This phenomenon is called the greenhouse effect.  The warm atmosphere will melt snow from the polar and high mountains, which will raise sea levels and flood low-lying areas.

29. What are the hazards of water pollution?  

Ans: The hazards of water pollution are as follows:  

Polluted water can cause water-borne diseases such as dysentery, cholera and jaundice.  

Pesticides such as DDT enter the water body with rainwater, and from there enter the food chain through producers and accumulate at various trophic levels. This is called biological surge , which seriously affects the body at the top of the food chain.  

Eutrophication-Excessive growth of phytoplankton due to wastewater discharge will reduce the level of dissolved oxygen, thereby affecting aquatic organisms.

30. What is the biogeochemical cycle? What is the nutrient cycle in the atmosphere?

Ans: The nutrient cycle between the inanimate environment (soil, air, water) and living organisms is called the biogeochemical cycle.

Where i) shows the Ammonifaction process while ii) shows denitrification.

31. Explain how to reduce the concentration of carbon dioxide in the atmosphere. 

Ans:  Ways to reduce the concentration of carbon dioxide- 

a) Photosynthesis-Plants absorb carbon dioxide from the air and use it to synthesize food.  

b) Fossils-Due to the pressure and temperature of the earth, dead plants and animals are converted into fossil fuels such as coal and oil.  

c) The carbon dioxide contained in the water is combined with the carbonate and graphite in the rock.

32. How do fossil fuels produce air pollution?  

Ans: The burning of fossil fuels has the following effects:  

a) The burning of fossil fuels releases nitrogen oxides and sulfur. This can cause breathing problems and acid rain.  

b) The burning of fossil fuels increases the amount of fine dust in the air, which can cause smog, reduced visibility and traffic accidents in winter.  

c) When burned, it releases carbon dioxide, which absorbs solar energy and increases the temperature of the earth.

33. Write down what will happen if the water is contaminated.  

Ans: When water is contaminated, the following events occur:  

a) Undesirable substances that can cause cholera are added to water bodies.  

b) It can remove required substances from water bodies and dissolve oxygen. , which is important for aquatic organisms and poses a danger to aquatic organisms.  

c) When water is polluted, the temperature of the water will change, which will adversely affect the  life forms in the water.

34. Write about the nitrogen cycle in nature?  

Ans: The nitrogen cycle is divided into the following stages:  

a) Nitrogen in the atmosphere is transformed into the protoplasm of green plants through nitrogen fixation.  

b) Protoplast is converted to ammonia by ammoniating.  

c) The ammonia is then converted to nitrite and then to nitrate.  

d) The nitrogen in the atmosphere is then directly converted into nitrate through nitrification.  

e) Nitrate is converted to nitrogen by denitrification.

35. What is the greenhouse effect? What happens if the amount of carbon dioxide in the air increases?  

Ans: The phenomenon that various gases absorb heat in the air and cause the earth's temperature to rise is called the greenhouse effect.  If the carbon dioxide content in the air rises, because carbon dioxide is a greenhouse gas, the greenhouse effect will increase and cause the earth’s atmospheric temperature to rise rapidly. That leads to the melting of glaciers and becoming a danger for various living organisms.

36. What is the role of ozone in the atmosphere? How is the ozone hole created?

Ans: The ozone layer absorbs harmful radiation from the sun and prevents it from reaching the surface of the earth, where it can harm living things. There are ozone layers, and an ozone hole has been discovered over Antarctica.

37. What is the role of the earth's soil in agriculture?  

Ans: Under the ground, the loose surface of the earth's crust is present. Soil is the nutrient medium for all plants. It provides material support and nutrients for plant growth, as well as sufficient air and water.

38. What is the difference between the Earth's atmosphere and the atmospheres of Venus and Mars?

Ans: The earth's atmosphere contains oxygen, which is necessary for life to exist on the planet. It is required during breathing and respiration, two of life's most important events. Mars atmosphere has as its main constituent, and thus life on Earth is not possible.

39. What is air pollution and how does it cause acid rain?  

Ans: The air is mixed with harmful substances, which changes the components of  air to make it harmful, which is called air pollution.  When fossil fuels such as coal and petroleum are burned, various nitrogen and sulfur oxides are formed, which are mixed with rainwater to form nitric acid and sulfuric acid, and then fall on the earth's surface in the form of acid rain. It is very dangerous because it can cause kinds of disturbances to living organisms and destroy buildings and monuments.

40. Why is carbon dioxide so vital to the survival of life on Earth? What are the two methods by which it is fixed on Earth?

Ans: Carbon dioxide aids in the heating of the earth's surface, which aids in the maintenance of a suitable temperature for life forms on Earth.It is also required for photosynthesis by plants.

It is fixed in two ways: 

(a) green plants convert to glucose in the presence of sunlight.

(b) Marine animals make use of carbonates dissolved in seawater to make shells.

5 Marks Questions

1. What is the nitrogen cycle? Explain the different steps.

Ans: Steps of the Nitrogen cycle

1) Ammonification – The process of converting complex organic compounds such as proteins. Ammonification is the process of converting ammonia into ammonia.

2) Nitrification – Nitrification refers to the process of converting ammonia into nitrites and nitrates.

It occurs in two steps:

 $\text{Ammonia} \underset{Nitrosomonas}{\longrightarrow} {\text{Nitrite}}$

$\text{Nitrite} \underset{Nitrobactor}{\longrightarrow} {\text{Nitrate}}$

3) Denitrification – The process of converting nitrite salts in soil and water to free nitrogen gas. This is done by bacteria pseudomonas.

2. Draw a carbon cycle.

Download Important Questions of Natural Resources Class 9 PDF

Natural resources class 9 important questions summary.

Earth is the only planet on which life exists and its important resources are land, water, and air. And some of the other resources that earth includes are fossil fuels, sunlight, wind, and minerals. Biofactors which are referred to as living things in the ecosystem and air, water, soil, etc forms the non-living or abiotic components of the biosphere.

Topics covered in the natural resources Class 9 Important questions are - Natural resources, The Breath of Life: Air, Water: A Wonder Liquid, Mineral Riches in the Soil, Biogeochemical Cycles, Ozone Layer.

Air and Air Pollution - The atmosphere is surrounded by a layer of gases. Some of the gases are 78% nitrogen, 21% oxygen, and 1% other gases by volume. The main role of the atmosphere is to keep the temperature steady. It also slows down the escape of the temperature of heat to outer space and it also prevents the sudden rise of temperature during the day.

Ozone Layer - It is a thin layer of the earth's atmosphere. The main function of the ozone layer is to provide a shield over the earth's stratosphere and absorb the greatest amount of the sun's ultraviolet rays. The ozone layer comprises a high concentration of ozone when compared to other parts of the atmosphere. When the amount of ozone is reduced in the stratosphere is known as ozone depletion. Which results in greater UV radiations reaching the earth’s surface. The main reason for ozone depletion is the greenhouse effect and CFCs.

Water: A Natural Resource - Water is the main component of our life in day-to-day activities. It forms two-thirds of our body and helps to keep our body temperature normal. It is also used for various purposes like agricultural, domestic, industrial, etc. earth has only three percent of freshwater, and the rest 97 percent of water resides in the ocean. When any impurities are mixed with water, this is caused by the discharge of pollutants directly or indirectly to freshwater without proper treatment. The main causes of water pollution are urbanization, industries, agriculture, religious and social practices.

Soil - It is the uppermost layer of the earth's surface. The formation of soil takes place by continuous weathering and it depends on the parent material, time, climate, and organisms. Soil is a mixture of organic matter and its basic components are minerals, inorganic matter, water, and air. The various types of soil are clay, loam, silt, sand, etc.

After going through all Class 9 Science Chapter 14 important questions , provides fully solved solutions to all questions. These important questions will help the student to save their time during exam preparation and those answers are designed in such a way that it improves the confidence of the student by solving them. If a student goes through all-important questions of natural resources class 9, he can easily score good marks in the board examinations.

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FAQs on Important Questions for CBSE Class 9 Science Chapter 14 - Natural Resources

1. What are Natural Resources according to Chapter 14 of Class 9 Science?

The resources that are provided to us by the nature and environment we live in are known as natural resources. These resources are essential for fulfilling our daily requirements and cannot be made by man. Some examples of natural resources include water, air, coal, fuel, soil, minerals, etc. Natural resources are further categorized into being renewable like solar energy, soil, trees, etc., and nonrenewable resources like oil, coal, aluminum, etc.

2. How can we protect natural resources from the information available in Chapter 14 of Class 9 Science?

Since natural resources cannot be created by man and take a lot of time to replenish, it is important for us to protect and conserve them. Some ways to do so are:

Plant more trees to avoid soil erosion

Use alternative power sources like solar and wind energy

Indulge in rainwater harvesting at home

Use biogas for cooking at home

Switch to energy-saving electronic appliances

Indulge in reusing and recycling

3. What are the 5 most important natural resources according to Chapter 14 of Class 9 Science?

The 5 most important natural resources are:

Water: It is the most important natural resource without a doubt since we require it on a daily basis for our survival.

Oil: The manufacturing and transportation industries are majorly dependent upon oil resources.

Coal: It is also an essential heat and fuel-providing resource.

Forests: These are not only a resource providing us with paper, wood, lumber, etc. but also a habitat to various species in the world. 

Iron: This has been a very useful resource for many generations now.

4. What are the two main problems with natural resources discussed in Chapter 14 of Class 9 Science?

There are many problems that can be associated with natural resources. Some of these include:

Exhaustion of the non-renewable natural resources caused by the exploitation of them is one the biggest issues and will lead to a damaging effect on the environment and the survival of all organisms.

All human activities like deforestation, air and water pollution, depletion of freshwater resources, climate change due to the increasing amount of human activity are also major problems with regard to natural resources and their use.

5. What are important topics covered in Class 9 Science Chapter 14?

The important topics covered in the Important Questions for CBSE Class 9 Science Chapter 14 - Natural Resources include the following:

Air pollution

Water pollution

Biogeochemical cycles

Greenhouse effect

Ozone layer depletion

These topics have a greater chance of being questioned in the exam in comparison to other topics. Hence, students must ensure that they prepare these topics and the important questions based on them to help them achieve better scores in the Class 9 Science exams. The solution notes or any study material is available for downloading from Vedantu absolutely free of cost.

CBSE Class 9 Science Important Questions

Cbse study materials.

Science Project On Natural Resources For Class 9

Table of Contents

Acknowledgment

I want to sincerely thank everyone who has assisted me in finishing my project on natural resources. First and foremost, I want to express my gratitude to my teacher for providing me with the chance to study and write about this significant subject.

I also want to express my gratitude to my parents for their unwavering support and inspiration during my academic career. They have been a tremendous source of inspiration and advice for me.

Last but not least, I want to thank my friends and classmates for their assistance and criticism during the research and writing process. Their advice and thoughts have been very beneficial in raising the calibre of this endeavour.

Once more, I would want to express my gratitude to everyone who helped finish our study on natural resources.

The existence and welfare of humans and other living things depend on natural resources. Everything we require for survival—from the oxygen we breathe to the water we drink, from the food we eat to the materials we use for our homes and clothing—is derived from the earth’s natural resources.

However, we are putting a greater strain on these resources as the world’s population continues to rise and as our economies develop. Our natural resources’ availability and sustainability are being threatened by environmental problems such as climate change, deforestation, pollution, overfishing, and others.

The significance of natural resources, the threats to our planet’s resources, and some of the actions we can take to safeguard and maintain these priceless resources for future generations will all be covered in this project. We want to inspire action to build a more sustainable future by raising awareness of the pressing need to solve these problems through our research and analysis.

Introduction

Natural resources are the earth’s raw materials and constituent parts that are vital to human survival and the well-being of all other living things. These resources include, among others, the air, water, soil, minerals, forests, and wildlife.

The accessibility and sustainability of these resources are more and more crucial as the global population and economies expand. We must effectively manage and utilise the limited natural resources we have given the rising demand and restricted supply.

However, a number of environmental problems, such as climate change, deforestation, pollution, overfishing, and habitat destruction are putting our planet’s natural resources in danger. These problems endanger not just the environment but also the health and welfare of people.

Natural Resource Categories

Renewable Resources: Resources that can regenerate themselves over time include sunlight, wind, water, and wood. Because they can be used without becoming completely depleted, these resources are typically regarded as sustainable.

Non-Renewable Resources: Non-renewable resources are limited and cannot be renewed. Examples include minerals like iron, copper, and gold, as well as fossil fuels like coal , natural gas, and oil. These resources cannot be replenished after they are used up.

Inexhaustible Resources: Resources that are basically unending, such as solar and geothermal energy, are known as inexhaustible resources. Although these resources do have some limitations, they are not likely to run out anytime soon.

Biotic Resources: Resources derived from living things, such as those found in forests, fish, and animals, are referred to as biotic resources. These resources are crucial for economic growth and human life, but in order to assure their long-term availability, they must be handled sustainably.

Abiotic Resources: Resources that are not produced by living organisms, such as minerals, water, and air, are referred to as abiotic resources. These resources must be maintained responsibly to prevent depletion and contamination because they are crucial for human survival and economic growth.

We can better manage and utilise natural resources to maintain their sustainability and long-term availability by knowing the various forms of natural resources.

Amount Of Natural Resources Important

Economic Value: Natural resources are crucial for economic growth since they supply the industries ‘ raw materials and support the creation of jobs. Governments and regional communities profit from the mining and processing of natural resources.

Environmental Value: Natural resources are essential parts of our planet’s ecosystem because they promote biodiversity and provide habitats for animals. They are essential for controlling the temperature, water cycle, and cycling of nutrients on Earth.

Social Value: Natural resources offer the essentials for life, including food, water, and shelter. Additionally, they support leisure pursuits like tourism and outdoor recreation.

National Security: Natural resources are crucial to maintaining national security because they provide the energy, minerals, and other key elements required for military and defence operations.

Human Health: Clean air and water, wholesome food, and natural medicines are all provided by natural resources, which are crucial for maintaining human health and wellbeing.

It is impossible to exaggerate the value of natural resources. They are vital to the existence and well-being of humans and other living things, and the sustainability of their management is key to our future.

Natural Resource Depletion

Natural resource depletion is a significant issue that imperils both the health of humans and other living things as well as the viability of our planet’s ecosystems . The following are some of the primary reasons of resource depletion:

Mismanagement: Natural resources, particularly non-renewable resources like fossil fuels, have been overused and poorly managed, which has resulted in their depletion. Additionally, a lot of resources are depleted because they are used up faster than they can be replenished.

Pollution: Many natural resources, such as air and water, have been degraded by pollution from industries, agriculture, and other human activities, rendering them unusable or hazardous to human health and the environment.

Destruction of Habitats: The loss of biodiversity and the depletion of numerous resources, including timber and wildlife, have been brought on by the destruction of habitats, notably forests.

Climate Change: The availability of water and agricultural productivity are two examples of how climate change is altering natural resources, which may result in their depletion or degradation.

Unsustainable Consumption: Global natural resource depletion is a result of unsustainable consumption practises, particularly in industrialised nations.

Natural resource depletion has detrimental effects on human and other living things’ health as well as the ecosystems of our world. In order to ensure that these resources are available for future generations, it is crucial that we take action to manage and use them sustainably.

Natural Resource Preservation

The appropriate management and use of natural resources is referred to as conservation in order to guarantee their persistence for future generations. Among the most important measures we may take to protect natural resources are:

Reusing and recycling items can assist to conserve natural resources and cut down on waste by reducing the amount of natural resources we utilise.

Sustainable Agriculture: Crop rotation and organic farming are examples of sustainable agricultural practises that can help to preserve soil and water resources.

Sustainable Forestry: By using techniques like selective logging and regeneration, one may preserve timber supplies and advance biodiversity.

Renewable Energy: Increased use of renewable energy can lessen our reliance on non-renewable resources and encourage sustainability. Examples of such renewable energy sources include solar and wind power.

Pollution Control: Pollution control can aid in the preservation of natural resources like air and water by lowering the pollution produced by businesses and other human activities.

Education and Awareness: Raising public awareness of the value of natural resources and the need to protect them can support their sustainable management and use.

The long-term sustainability of our planet’s ecosystems and the health of humans and other living things depend on the conservation of natural resources. We can contribute to ensuring that these resources are accessible for future generations to enjoy by adopting sustainable practises, raising awareness of the issue, and encouraging education.

Natural Resources Examples

Water is a critical natural resource for human survival, agriculture, and many other sectors.

Another crucial natural resource is air, which contributes to climate regulation and supplies oxygen for both human and animal life.

Soil: Soil is a vital natural resource that promotes plant development and serves as the basis for many different businesses, including agriculture.

Fossil Fuels: Non-renewable natural resources utilised in the generation of energy include coal, oil, and natural gas.

Minerals: Natural resources like iron, copper, and gold are employed in a variety of industries, from electronics to building.

Timber: Timber is a naturally occurring resource that may be obtained from forests and utilised for a variety of tasks, including paper making and construction.

Animal: Wildlife is a natural resource that supports cultural and leisure activities like hunting and animal viewing while also providing ecological functions like pest control and pollination.

Renewable Energy Sources: Renewable energy sources are natural resources that are used to provide clean energy. Examples include solar, wind, and hydropower.

These are but a few instances of the numerous natural resources that are available and crucial to human existence and economic growth. In order to ensure that these resources are available for future generations, it is crucial that we manage and utilise them sustainably.

Conclusion And Prospects

Natural resources are crucial to the continued existence and welfare of humans and other living things. In addition to offering ecological services that support the ecosystems on our world, they also offer food, water, shelter, and energy. The sustainability of our world is now in jeopardy due to the overuse and poor management of natural resources, which has caused their degradation and depletion.

For natural resources to be available to future generations, they must be conserved. We can contribute to the preservation of these resources and the preservation of our planet’s ecosystems by implementing sustainable practises and encouraging awareness and education.

In order to manage and use natural resources sustainably in the future, it is crucial that we continue to develop and adopt sustainable practises. This entails encouraging the use of renewable energy sources, sustainable forestry and agricultural practises, and lowering pollution from businesses and other human endeavours. It also entails keeping up public awareness campaigns about the value of and need for protecting natural resources.

In conclusion, natural resources are essential to the ecosystems of our globe as well as the health of humans and other living things. For the benefit of both current and future generations, we must collaborate to sustainably manage and maintain these resources.

Certificate

This is to certify that I, [Your Name], a student of Class 9 at [Your School Name], have successfully completed the science project on “Natural Resources. ” The project was undertaken as part of my academic curriculum to explore and understand the significance of natural resources, their depletion, and the importance of conservation.

I would like to express my heartfelt gratitude to my teacher, [Teacher’s Name], for providing me with the opportunity to delve into this critical topic and expand my knowledge on the subject matter. Their guidance, encouragement, and valuable insights have been instrumental in the successful completion of this project.

I am also deeply thankful to my parents for their constant support and motivation throughout my academic journey. Their encouragement and belief in my abilities have been a constant source of inspiration.

Furthermore, I extend my appreciation to my friends and classmates for their assistance and constructive feedback during the research and writing process. Their input has been invaluable in enhancing the quality of this project.

I am thrilled to have worked on this project, as it has allowed me to understand the importance of natural resources, the threats they face, and the measures we can take to protect them. It is my hope that this project will raise awareness and inspire others to take action in preserving our planet’s precious resources for future generations.

Date: [Date]Place: [Your City] [Your Signature](Your Name)

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KSEEB Solutions

KSEEB Solutions for Class 9 Science Chapter 14 Natural Resources

Karnataka board class 9 science chapter 14 natural resources, kseeb solutions class 9 science chapter 14 intext questions.

Question 1. How is our atmosphere different from the atmospheres on Venus and Mars? Answer: Both Venus and Mars have 95.97% of the carbon dioxide. But in our earth 0.02% of carbon dioxide is present. Our earth has 21% of oxygen which is necessary for all living beings. In this way, Earth’s atmosphere is different from the atmosphere on Venus and Mars.

Question 2. How does the atmosphere act as a blanket? Answer: Atmosphere is covering the earth, like a blanket, we know that air is a bad conductor of heat. The atmosphere keeps the average temperature of the earth fairly steady during the day and even during the course of the whole year. The atmosphere prevents the sudden increase in temperature during the daylight hours. And during the night, it slows down the escape of heat into outer space.

Question 3. What causes winds? Answer: In the coastal regions, during the day, the air above the land gets heated and starts rising. As this air rises, a region of low pressure is created and air over the sea moves into this area of low pressure. The movement of air from one region to the other creates winds,

Question 4. How are clouds formed? Answer: When water bodies are heated during the day, a large amount of water evaporates and goes into the air-some amount of water vapour also get into the atmosphere because of various biological activities. This air also gets heated. The hot air rises up carrying the water vapour with it. As the air rises, it expands and cools. The cooling causes the water vapour in the air to condense in the form of tiny droplets. This condensation of water is facilitated if some particles could act as the nucleus for these drops to form around. Normally dust and other suspended particles in the air perform this function.

Question 5. List any three human activities that you think would lead to air pollution. Answer: Following are the three human activities which leads to air pollution.

• Burning of fossil fuels leads to air pollution.
• By the destruction of forests.
• By industrialisation.

Question 6. Why do organisms need water? Answer: All cellular processes take place in a water medium. All the reactions that take place in a water medium. All the reactions that take place within our body and within the cells occur between substances that are dissolved in water.

Substances are also transported from one part of the body to the other in a dissolved form. Hence organisms need to maintain the level of water within their bodies in order to stay alive. Hence organisms need water.

Question 7. What is the major source of freshwater in the city/town/village where you live? Answer: In some places, the river is the major source of fresh water. In some places, freshwater is available from borewells. Tungabhadra river is the major source for us. (Gadag district)

Question 8. Do you know of any activity which may be polluting this water source? ‘ Answer:

• The addition of undesirable substances to water bodies. These substances could be the fertilizers and pesticides used in farming or they could be poisonous substances like mercury salts which are used by paper industries.
• Releasing drainage water and effluents from industries to nearby water resources.
• Releasing superheated water to rivers.
• Change in temperature of river water. These are the activity from which water gets polluted.

Question 9. How is soil formed? Answer: Over long periods of time thousands and millions of years, the rocks at or near the surface of the Earth are broken down by various physical, chemical, and some biological processes. The end product of this breaking down is the fine particles of soil. The Sun, water, and wind are also factors helpful for the formation of soil.

Question 10. What is soil erosion? Answer: Flowing water and blowing wind carries soil particles along with them. This is called soil erosion.

Question 11. What are’ the methods of preventing or reducing soil erosion? Answer:

• The roots of plants have an important role in preventing soil erosion.
• We should give importance to reforestation. Afforestation programmes instead of deforestation.
• Vegetative cover on the ground has a role to play in the percolation water into the deeper layers too. In the hilly or mountainous region, we should grow more grass. By these methods, we can prevent or reduce soil erosion.

Question 12. What are the different states in which water is found ‘during the water cycle? Answer: Water is found in solid, liquid, and gaseous states during the water cycle.

Question 13. Name two biologically important compounds that contain both oxygen and nitrogen. Answer:

• Carbon dioxide
• Phosphorus pentoxide.

Question 14. List any three human activities which would lead to an increase in the carbon dioxide content of air. Answer:

• Burning of fuels
• Overuse of vehicles.

Question 15. What are the greenhouse effects? Answer: Some gases prevent the escape of heat from the earth. An increase in the percentage of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect.

Question 16. What are the two forms of oxygen found in the atmosphere? Answer: Carbon dioxide and water vapour are the two forms of oxygen found in the atmosphere.

KSEEB Solutions for Class 9 Science Chapter 14 Textbook Exercises

Question 1. Why is the atmosphere essential for life? Answer: (a) to establish all forms of life. (b) necessary vital components can be – recycled. (c) maintenance of temperature. (d) a suitable environment for all forms of life. (e) ozone a protective layer.

Question 2. Why is water essential for life? Answer: All organisms require water for their survival. All cellular processes take place in a water medium. All the reactions that take place within our body and within the cells occur between substances that are dissolved in water. Substances are also transported from one part of the body to the other in a dissolved form. In this way water is essential to us.

Question 3. How are living organisms dependent on the soil? Are organisms that live in water totally independent of soil as a resource? Answer: Soil supplies various nutrients which are essential for all organisms. Even soil is necessary for the fixing of plants firmly and increases the level of underground water. Even organisms that live in water are also totally dependent of soil as a resource. They are not surviving without soil.

Question 4. You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather? Answer: Because of scientific equipment, we come to know about the weather reports. For example, if there is a depression in a barometer, we may expect heavy rainfall. By such phenomena, we are able to predict the weather.

Question 5. We know that many human activities lead to increasing levels of pollution of the air, water-bodies, and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution? Answer:

• Farmers should use pesticides and insecticides judiciously so that no soil pollution takes place.
• We should not allow effluents (wastes from industries) to mix with river water. Superheated water should not mix with river water.
• We can prevent air pollution by tree plantation programmes. All these are the preventive measures to avoid soil, water, and air pollution.

Question 6. Write a note on how forests influence the quality of our air, soil, and water resources. Answer: Forests are useful to us in many ways. They are as follows:

• Plants take carbon dioxide which we give out during respiration and we get oxygen from plants which are very essential to us.
• Plants increase water content in the underground. Roots of the plants minimize soil erosion and there is an increase in the water holding capacity.
• Because of the number of trees, no soil erosion takes place. Roots bind soil particles and more water is stored.

KSEEB Solutions for Class 9 Science Chapter 14 Additional Questions and Answers

Fill in the blanks with suitable words: Question 1. Nearly _________ % of earth’s surface is covered with water. Answer: 75 %.

Question 2. Air _______ and ______ as it goes up. Answer: expands, cools

Question 3. When the temperature of the air is low enough, precipitation may occur in the form of _____, ______ or _____ Answer: snow, sleet, hail.

Question 4. If we intake polluted air continuously, we have to suffer from diseases like ______ and ______ Answer: Allergy, cancer and heart disease.

Question 5. The outer covering of the earth is called ______ Answer: crust.

Answer the following questions:

Question 1. What is the importance of Humans? Answer : It is a major factor in deciding the soil structure because it causes the soil to become more porous and allows water and air to penetrate deep underground.

Question 2. Write the importance of topsoil? Answer : The topmost layer of the soil that contains humus and living organisms in addition to the soil particles is called topsoil, it is important to factor that decides biodiversity in that area.

Question 3. Mention the two important components of biogeochemical cycles. Answer :

• Reservoir pool
• Exchange pool

KSEEB Solutions for Class 9 Science

Assignment - Natural Resources, Class 9, Science PDF Download

                                                            EXTRA PRACTICE QUESTIONS

                                                 NATURAL RESOURCES : CLASS 9, SCIENCE

  Fill in the blanks

1.  In some terrestrial ecosystems more than ............ percent of the moisture passes through plants.

2.  Water is a compound of two vital elements ............ and ............

3.  Conversion of atmospheric nitrogen into nitrogen compounds by living organisms is called ............

4.  The process of conversion of ammonia into nitrites and nitrates is called nitrification. It is carried out by the action of ............ and ............

5.  Denitrification is carried out by ............ bacteria.

6.  The plants use ............ as one of the raw materials for the process of photosynthesis and prepare carbohydrates.

7.  Both plants and animals release carbondioxide in the atmosphere by the process of ............

8.  Water forms ............ percent of the cell content.

9.  In nature, oxygen occurs in the gaseous form constituting ............ percent of the total atmosphere.

10.  Ozone layer is about ............ km thick. It absorbs harmful radiations come from the sun.

1.  90 

2.  Hydrogen, Oxygen 

3.  Ammonification 

4.  Fungi & bacteria 

5.  Pseudomonas

6.  Carbondioxide 

7.  Respiration 

8.  60 90 

9.  21 

10.  5

Fill in the blanks

1.  The outer most layer of our earth is called ......................... .

2.  Soil serves as ............................. habitat for microbes, plants and animals.

3.  All cellular processes take place in ......................... medium.

4.  The quality of the topsoil is an important factor that determines .................... of that area.

5.  The reason of cracking of rocks is ......................... by the sun.

Ans.   1.  Earthcrust  2.  Natural  3.  Water  4.  Biodiversity  5.  Uneven heating

Find out True and False statements from followings

1.  Weathering involves a number of physical, chemical and biological processes.

2.  Lichen release Alkaline substances that causes the rock surface to powder down.

3.  Chemical fertilizers increase fertility instaneously.

4.  The nutrient contents of the soil do not depend upon the type of rock.

5.  The scientific study of soil is called ecology.

6.  Earth is also known as water planet as water covers about 97% of the earth's surface.

7.  Most metabolic activities at the cellular level occur in liquid medium.

8.  Presence of excessive amount of nutrients in water is called eutrophication.

9.  Intensive agriculture exhausts minerals which leads decrease soilfertility.

10.  Terracing of sloping land of hills reduces the speed of water.

Ans.   1.  T  2.  F  3.  T  4.  F  5.  F

6.  F  7.  T  8.  T  9.  T  10.  T

VERY SHORT ANSWER TYPE QUESTIONS 1. Name the substances which are responsible for damaging ozone layer. 2. What are different stages in which water is found during the water cycle? 3. Where ozone hole was first discovered? 4. What are the two forms of oxygen found in the atmosphere? 5. What is the ultimate source of energy for organisms? 6. Give definition of Bio-Geochemical cycle. 7. Name a free-living bacterium which helps in nitrogen fixation. 8. Name the main reservoir of gaseous carbon. 9. Name any two Green house gases. 10. What is green house effect?

SHORT ANSWER TYPE QUESTIONS 1. Mention few harmful effects which are caused due to depletion of ozone layer. 2. Write a short note on water cycle. 3. Write a short note on Green house effect. 4. Write a short note on carbon cycle. 5. Name the micro-organisms which are involved in :- (a) Biological nitrogen fixation (b) Nitrification (c) Denitrification

LONG ANSWER TYPE QUESTION 1. Draw a labelled diagram to show : (a) Nitrogen cycle in nature. (b) Carbon cycle in nature. (c) Oxygen cycle in nature. 2. Explain nitrogen cycle. 3. Write an essay on ozone layer.

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Natural Resources Chapter 14 Class 9 Science Assignments

Please refer to Natural Resources Chapter 14 Class 9 Science Assignments below. We have provided important questions and answers for Natural Resources which is an important chapter in Class 9 Science. Students should go through the notes and also learn the solved assignment with solved questions provided below. All examination and class tests questions are as per the latest syllabus and books issued by CBSE, NCERT, and KVS. We have also provided Class 9 Science Assignments for all chapters on our website.

Chapter 14 Natural Resources Class 9 Science Assignments

Question. Name two biologically important compounds that contain both oxygen and nitrogen.

Proteins and nucleic acids (DNA and RNA).

Question. The atmosphere acts as a blanket, how?

Air is a bad conductor of heat which keeps average temperature of the Earth steady during day and at night. The ozone shield of the atmosphere absorbs most of the harmful radiations coming from Sun.

Question. List any two traditional systems of water harvesting.

Two traditional systems of water harvesting are : Collection of water in ponds and construction of small Earthen dams.

Question. Define anaerobic degradation.

Breakdown of organic matter by microorganisms when oxygen is not present is known as anaerobic degradation.

Question. Name the three processes which used oxygen.

Combustion, respiration and in the formation of oxides of nitrogen.

Question. What is the greenhouse effect?

Some gases prevent the escape of heat from the Earth.An increase in the percentage of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect.

Question. Give two natural resources available on the Earth.

Water and air.

Question. State two reasons each of conserving (a) forest and (b) wildlife.

Two reasons each of conserving : (a) Forest (i) It helps in retaining the sub-soil water. (ii) It checks flood. (b) Wildlife (i) To maintain ecological equilibrium. (ii) To protect the nature.

Question. Why does Moon have very cold and very hot temperature variations, e.g., from –190°C to 110°C even though it is at the same distance from the Sun as the Earth is?

Absence of atmosphere on the Moon.

Question. Identify which of the following are not the part of biotic environment : soil, plants, fish, air, insects.

Question. Name two oxides formed by burning of fossil fuels, which are responsible for acid rain.

The oxides of nitrogen and sulphur : (i) Sulphur dioxide and sulphur trioxide. (ii) Nitrous oxide and nitrogen dioxide.

Question. State an instance where human intervention saved the forests from destruction. Answer.  Human intervention saved the Arabari forest range of West Bengal from destruction with active and willing participation of local community. The Sal forest of Arabari underwent a remarkable recovery.

Question. What are the consequences of global warming? Answer. (i) An increase in temperature of Earth even by 1°C may lead to melting of ice on the poles. (ii) The melting of ice will result in rise of sea level. (iii) Due to rise in sea level, many coastal cities will be flooded or submerged. (iv) Increase in temperature of Earth, results the changes in weather and may cause excessive raining or drought or extreme hot or cold weather conditions.

Question. What is ozone hole? Where is it found? What is its effect? Answer.  There is a layer of ozone in the upper regions of the atmosphere which gets depleted due to chlorofluorocarbons and created a hole that is called ozone hole. It is found above North Pole.

Question. Which cycle is known as the perfect cycle in biosphere? Why? Answer.  Nitrogen cycle is known as the perfect cycle in biosphere as it maintains the amount of nitrogen in atmosphere, water and soil.

Question. How is reuse better than recycling? Answer.  ‘Sustainable management’ is the management of resources in which development can be maintained for a long time without undue damage to the environment.Recycling needs additional energy to make a usable item. Reuse does not require additional energy and hence, is better than recycle.

Question. How did ‘Chipko Andolan’ ultimately benefit the local people? Describe briefly. Answer.  Chipko Movement : (i) During 1970, in Reni village of Garhwal, a contractor was allowed to cut trees in a forest near the village. (ii) When the contractor’s workers went to the forest to cut trees, the women of the village hugged the tree trunks to prevent the workers from cutting trees. (iii) Chipko means ‘hug’ and the movement began with the villagers hugging trees. It is called the ‘Chipko Andolan’. (iv) The movement benefited the local population as it conserved the forest products. It benefited the environment as it conserved the quality of soil and sources of water thereby, maintained balance in nature.

Question. Name four human activities which cause air pollution. Answer. Mining :  Mining activities release dust. Thermal power plants :  Air pollution caused by burning of fossil fuel. Firework on festivals :  It results in the release of toxic chemicals into air.Burning of fossil fuel : In industries, automobiles,domestic purposes, etc.

Question. Name the stages of the life cycle of aquatic animals which are affected by change in temperature. Answer.  The eggs and larvae of various aquatic animals are sensitive to temperature changes. Sudden change in the temperature in the water body would be dangerous for them or affect their breeding.

Question. Which of the two is a better option, (i) to collect rainwater in ponds or artificial lakes, or (ii) to let it recharge groundwater by water harvesting? List two advantages of the option to justify your Answer. Answer. To allow rainwater to recharge groundwater by water harvesting is the better option. Its advantages are : (i) Groundwater does not evaporate. (ii) Groundwater does not provide breeding ground for mosquitoes.

Question. How is soil formed? Answer. The rocks near the surface of the Earth are broken down by various physical, chemical and some biological processes over long periods of time, thousands and millions of years. Finally, fine particles of soil formed.There are many other factors which play a vital role in the formation of soil. These factors are : (i) The Sun heat, (ii) Water, (iii) Wind, (iv) Living organisms.

Question. List any two causes of our failure to sustain availability of underground water. Answer.  Two causes of our failure to sustain availability of underground water are : (i) Rising population : As the population increases, demand for water increases resulting in depletion of underground water level. (ii) Industrialization : Industries need more and more water to manufacture products. With growing industrialization, demand for water increases which results in reduction in the availability of underground water.

Question. Define biosphere. Name its components. Answer.  Biosphere is global ecological system integrating all living beings and their relationships, including their interaction with the elements of lithosphere, geosphere, hydrosphere and atmosphere. The two components of biosphere are : (i) Biotic :  All living organism such as plants, animals and microorganisms. (ii) Abiotic :  Air, water and the soil.

Question. Do you know any activity which may be polluting water sources? Answer. There are many activities which cause pollution of water sources such as : (i) Dumping of waste from factories, sewage from our towns and cities into rivers, (ii) Discharging polluting water from cooling towers into the water bodies affects the breeding capacity of aquatic organisms.

Question. What are the different states in which water is found during the water cycle? Answer. Three different states of water can be seen during the water cycle. These states are : (i) Gaseous state :  Form of water vapour which evaporates from the surface water, (ii) Liquid state :  Formed by the condensation of water vapour and can be seen in the form of rain, (iii) Solid state :  Formed by the freezing of liquid droplets in the upper layer of atmosphere which can be seen in the form of snow, hail.

66. What causes winds? Answer.  Winds are caused due to uneven heating of atmospheric air. This phenomenon can be seen near coastal regions during the daytime. The air above the land gets heated faster and starts rising. A region of low pressure is created as this air rises, and air over the sea moves into this area of low pressure. The movement of air from one region to the other creates winds. During the day, the direction of the wind would be from the sea to the land.

Question. “Soil is formed by water.” If you agree to this statement then give reasons. Answer. Water helps in the formation of soil in the following ways : (i) Water causes ‘wear off’ of rocks over a long period of time. (ii) It also causes the rocks to rub against other rocks creating small particles which are taken away downstream and deposited as soil. (iii) Water expands on freezing in crevices of rocks and break rocks into smaller pieces.

Question. What causes movement of air? Mention the factors which influence these winds? Answer. (i) Uneven heating of the atmosphere. (ii) Rotation of the Earth. (iii) Presence of mountain range. (iv) Difference in cooling and heating of land and water bodies. (v) Formation and condensation of water vapours.(any two)

Question. How is the atmosphere of Venus/Mars different from that of the Earth? Name two main gases present in Earth’s atmosphere. Answer.

Question. What are the adverse effects of products of combustion of fossil fuels on the environment? Answer.  When fossil fuels are burnt, carbon dioxide, water,oxides of nitrogen and oxides of sulphur are formed.If the combustion takes place in insufficient air, then carbon monoxide is formed instead of carbon dioxide. Of these products, the oxides of sulphur and nitrogen and carbon monoxide are poisonous gases and carbon dioxide is a greenhouse gas.

Question. What is ‘Chipko Movement’? Why should we conserve forests? Answer. ‘Chipko Movement’ is a non-political public movement for conservation of natural habitat and wildlife by preventing excessive commercial exploitation of forests. Chipko means ‘hugs’ and the movement were started by the villagers of Garhwal by hugging trees to stop the contractor’s workers from cutting the trees. We should conserve forests because it helps in protection of land, retaining sub-soil water, checking floods, and thereby maintain a balance in the ecosystem.

Question. Give two examples each of the Renewable sources of energy and Non-renewable sources of energy. Answer. (i) Geothermal energy, wind energy (ii) Coal, petroleum

Question. Write any four advantages of water stored in the ground. Answer.  Four advantages of storing water in the ground are : (i) It does not evaporate. (ii) It is relatively protected from contamination by human and animal wastes. (iii) It does not provide breeding ground for mosquitoes. (iv) It provides moisture for vegetation.

Question. What is meant by exploitation of resources with shortterm aims? List its four advantages. Answer.  Exploitation of resources with short-term aims means consumption of resources for immediate requirement without their conservation for future. Its four advantages are : (i) It fulfils the requirement of mass population. (ii) It provides industrial growth. (iii) It provides economic development. (iv) It makes life comfortable.

Question. Define weathering. Write the different means which cause weathering. Answer.  The process of breaking down of rocks into small, fine mineral particles is called weathering. The weathering may occur due to physical, chemical or biological means.

Question. Why must we conserve our forests? List any two causes for deforestation to take place. Answer.  We must conserve our forests as they are of great value. The reasons for conserving forests are : (i) Forests help in protection of land and retaining sub-soil water. (ii) Forests check floods and maintain ecosystem. Therefore, forests must be conserved for economic and social growth. Two causes for deforestation taking place are : (i) For industrial needs. (ii) For development projects like building of roads or dams.

Question. Name any two forest products, each of which is the basis for some industry. Answer. (i) Pine wood for matchbox industry. (ii) Bamboo for paper industry.

Question. Describe how lichens and big trees influence the formation of soil. Answer. (i) Lichens grow on the surface of rocks and release substances that breaks down the rock surface. (ii) Moss grows on this surface and breaks it further. (iii) The roots of trees grow into rocks, form cracks and widen them further to form soil.

Question. State two changes you can make in your habits to reduce the consumption of electricity or water. Answer.  Two changes that can be made to reduce the consumption of electricity or water are : (i) Switch off lights and fans when not in use. (ii) Leaked taps should be repaired immediately.

Question. List the causes that affect the life forms that are found in water bodies in various ways. Name the element present in coal other than carbon that releases harmful gases during combustion of coal. Answer. (i) Excess of fertilizers and pesticides used in the farms are washed into water bodies. (ii) Dumping of sewage from dwelling places into water bodies. (iii) Release of contaminated water from industries. (iv) Release of water from dams affects the temperature of river. (v) Sulphur and nitrogen.

Question. Give any four changes that you would like to incorporate in the lifestyle of students of your age to move towards a sustainable use of available resources. Answer. (i) Follow the principle of three ‘R’s – Reduce,Recycle and Reuse. (ii) Plant more trees. (iii) Use public transport, school bus and car pools. (iv) Switch off unnecessary lights and fans, thereby save electricity.

Question. List any four benefit of water harvesting. Answer.  Benefits of water harvesting are : (i) It provides drinking water. (ii) It provides irrigation water. (iii) It is responsible for the increase in groundwater level. (iv) It reduces storm water discharge, urban flood and overloading of sewage treatment plants.

Question. What are the methods of preventing or reducing soil erosion? Answer.  The methods of preventing soil erosion are : (i) Afforestation :  Plants reduce erosion as the roots of plants bind the soil in place. (ii) Shelter belts :  Trees planted in lines around farmland reduce erosion by reducing the speed of the wind. (iii) Contour ploughing :  Farmers plough land so that furrows lie across the natural slope of the land which do not allow it to flow down carrying the topsoil. (iv) Terrace farming :  A terraced hillside is a series of steps formed by horizontal strips supported by walls. It gives the water sufficient time to percolate into the soil and nourish the crop. (v) Soil cover :  Soil left bare after harvesting a crop is often covered with dried vegetation to prevent erosion. (vi) Preventing overgrazing :  Even a very little grass on a field prevents erosion of soil as the grass has a tendency to bind soil molecules.

Question. Write a note on “how forests influence the quality of our air, soil and water resources”. Answer.  Forests influence the quality of air, soil and water resources in the following ways : (i) Influence of forests in controlling the quality of air: (a) Forests help in minimising the level of CO 2  in the atmosphere which help to reduce greenhouse effect and global warming. (b) Forests reduce environmental temperature which increases the rate of photosynthesis in plants in the surrounding regions. (c) Some of the trees have the ability to absorb harmful gases present in the atmosphere, e.g., Jamun trees can absorb compounds of lead easily. (ii) Influence of forests in controlling the quality of soil : (a) The roots of trees prevent erosion of topsoil (b) Forests also regulate biogeochemical cycles (c) Many of the decomposing bacteria and nitrogen-fixing bacteria live in close association with the roots of the trees. (iii) Control the quality of water : (a) Forests help in returning pure water back to the surface of Earth through rains. (b) Forests help in maintaining the water cycle as well as water resources of the Earth.

Question. Mention any three human activities which are responsible for water pollution. Answer. (i) Excessive use of fertilizers and pesticides. (ii) Disposal of industrial waste which contains poisonous substances into nearby water bodies. (iii) Sewage discharged into sewers from household/ domestic units. (iv) Synthetic soap and detergents used during washing in household units. (v) Hot water released from industrial units.

Question. (a) Explain the formation of acid rain. (b) What does the presence of smog in an area indicate? Answer. (a) Acid rain is the rainwater which have excessive amount of acids/i.e., sulphuric acid and nitric acid. These acids are formed by the reaction of oxides of sulphur and nitrogen with water. The oxides of sulphur and nitrogen are produced by combustion of fossil fuels in industries, automobiles, thermal power plants and domestic appliances, etc. The sulphur and nitrogen, present in fossil fuels form these oxides by reacting with oxygen of air by the process of combustion. (b) The presence of smog in an area indicates the high percentage of smoke released in the air by combustion of fossil fuel in industries or automobiles. It is an indicator of air pollution.

Question. (a) What is the outermost layer of our Earth called? (b) How is this important to life forms? (c) Name four factors that help in the formation of soil from rocks. Answer. (a) The outermost layer of our Earth is called crust.The outer crust of Earth is called lithosphere. (b) The living forms get all substances of their requirement for supporting life form this region. (c) (i) Winds, (ii) Water, (iii) Living organisms, (iv) Temperature variations (due to solar radiation).

Question. How does nitrogen fixation take place during lightning?How do plants make use of the nitrates and nitrites present in soil? Answer.

Figure: Nitrogen Cycle in Nature The high temperatures and pressure created in the air convert nitrogen into oxides of nitrogen during lightning. These oxides dissolve in water to give nitrous and nitric acids that fall on land with rain.Nitrogen fixing bacteria which are found in the roots of leguminous plants convert atmospheric nitrogen into nitrate (the usable form by plants).The plants use nitrogen in the form of nitrates and nitrites to form amino acids and proteins. The plants are used as food by animals. The bacteria convert these compounds of nitrogen into nitrates and nitrites, after the death of plants and animals. Some other types of bacteria convert nitrites and nitrates into molecular nitrogen, which escapes into atmosphere and becomes a part of it.

Question. ‘A change in temperature in the water body affects aquatic organisms.’ Explain in brief. Answer. Change in the water temperature can affect the aquatic life in the following ways : It can encourage the growth of some life forms and harm some other life forms. This affects the balance between various organisms which had been established in that system.This can lead to removal of desirable substances like oxygen and other nutrients from water bodies. The eggs and larvae of various animals are particularly susceptible to temperature changes.So such aquatic life forms may become extinct from the related water bodies. Thus, the breeding of aquatic organisms will be affected.

Question. Write in brief the harmful effects of water pollution. Answer. (i) Causes water borne disease. (ii) Destroys microorganisms thereby affecting self purification of water. (iii) Decreases amount of dissolved O 2  in water bodies. (iv) Changes the temperature of water, oceans, leading to melting of polar ice. (v) Disturbs aquatic life. (vi) Kills aquatic organisms.

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