Get summaries, questions, answers, solutions, notes, extras, PDF and guide of Chapter 7 Natural Resources, NBSE Class 9 Environmental Education textbook, which is part of the syllabus of students studying under Nagaland Board. These solutions, however, should only be treated as references and can be modified/changed.
If you notice any errors in the notes, please mention them in the comments
Summary
Natural resources are things in nature that help humans live and grow. A resource is not useful by itself. It becomes useful when people use it for a purpose. For example, oil was not a resource until people started using it. Natural resources can be divided into two groups. These are inexhaustible and exhaustible resources. Inexhaustible resources like sunlight and wind do not run out. Exhaustible resources can be renewable or non-renewable. Renewable resources like water and plants can be replaced. Non-renewable resources like coal and oil cannot be replaced once they are used up.
Air is made of gases like nitrogen, oxygen, and carbon dioxide. Oxygen helps living things breathe. Nitrogen makes up most of the air but does not react much. Carbon dioxide helps plants grow and keeps the Earth warm. Air pollution happens because of cars, factories, and farming. Polluted air harms people, animals, and plants. Water covers most of the Earth but only a small part is fresh and usable. Freshwater comes from rain and is stored in rivers, lakes, and underground. People use water to drink, clean, and make electricity. But water is becoming scarce because of pollution and overuse.
Soil supports plants and stores water and nutrients. It is made of broken-down rocks, dead plants, and tiny spaces for air and water. Soil helps plants grow and gives homes to many creatures. But soil is being polluted by chemicals and waste. Cutting down trees causes soil erosion. Eroded soil fills rivers and dams, causing floods.
Forests are large areas covered with trees. They give homes to plants and animals. Forests protect soil, store water, and help control the climate. Trees take in carbon dioxide and give out oxygen. Forests also provide wood, food, and materials for making things. But deforestation is harming forests and the life inside them.
Minerals and metals come from rocks in the Earth. People dig them up through mining. Coal, oil, and natural gas are fuels. Coal is used to make electricity and steel. Oil is turned into fuel for cars and raw material for products like plastic. Natural gas is used for cooking, heating, and making chemicals. These fuels will run out one day because they take millions of years to form.
People must save natural resources. They should plant more trees and stop wasting water and energy. Farmers should use fewer chemicals on crops. Everyone should recycle and use renewable energy like solar and wind power. Saving resources today will help future generations live better.
Textbook solutions
Multiple Choice Questions (MCQs)
1. Gases that made the 99% of air are:
A. Nitrogen and argon
B. Oxygen and argon
C. Nitrogen and oxygen
D. Carbon dioxide and oxygen
Answer: C. Nitrogen and oxygen
2. __________ is the ultimate source of all freshwater.
A. Groundwater
B. Rain
C. Sea
D. Lake
Answer: B. Rain
3. __________ percent of the weight of living organisms is water.
A. 80%
B. 90%
C. 85%
D. 70%
Answer: B. 90%
4. Process of obtaining minerals from the earth is called __________.
A. Mining
B. Refinery
C. Liquefaction
D. Gasification
Answer: A. Mining
5. Around __________ percent of India’s bauxite reserves lie in the southern parts of Odisha.
A. 75
B. 80
C. 70
D. 85Answer: B. 80
Very Short Answer Questions
1. Describe the composition of air.
Answer: Air is composed of many gases. Nitrogen and oxygen are the major gases that make up 99% of air. Other important gases are carbon dioxide, ozone, helium, argon, methane, etc. Another constituent of air is water vapour. Dust particles are also present in the lower atmosphere.
Composition of air:
- Nitrogen – 78%
- Oxygen – 21%
- Argon – 0.9%
- Carbon dioxide – 0.03%
- Neon – 0.001%
- Helium – 0.0005%
- Ozone – 0.00006%
2. Name the major pollutants of air.
Answer: The major pollutants of air are sulphur dioxide, nitrogen oxide, carbon dioxide, fly ash, and suspended particulate matter (SPM). Smog, which is a smoky mixture of carbon monoxide and organic compounds due to incomplete burning of fossil fuels, is also a concern. Additionally, chlorofluorocarbons (CFCs), used in spray cans and refrigeration, contribute to air pollution by depleting the ozone layer.
3. What is suspended particulate matter?
Answer: Suspended particulate matter (SPM) is one of the major pollutants of air.
4. What is the chief source of water?
Answer: Rain is the ultimate source of all freshwater.
5. What is mining?
Answer: Process of obtaining minerals from the earth is called mining.
Short Answer Questions
1. Why is air pollution more in cities?
Answer: Air pollution is more severe in the urban areas as compared to rural areas. Maximum pollution can be seen in the industrial areas of the cities. Major pollutants of air are sulphur dioxide, nitrogen oxide, carbon dioxide, fly ash, and suspended particulate matter (SPM). Smog is often seen in big cities, which is a smoky mixture of carbon monoxide and organic compounds due to incomplete burning of fossil fuels. Nowadays, another pollutant called CFC (chlorofluorocarbons) is added to the air, which is used in spray cans and refrigeration and causes depletion of the ozone layer.
2. What is the role of carbon dioxide gas in air?
Answer: Carbon dioxide is used for the process of photosynthesis, therefore, required by all green plants. It also absorbs the radiant energy of the earth and re-radiates it back to the earth. Therefore, it is also called the greenhouse gas. It increases the temperature of the lower atmosphere.
3. Why is there water scarcity in big cities?
Answer: With the changing time, the availability of freshwater is decreasing. There are limited reserves of freshwater, and they too are getting polluted. Discharge of municipal and industrial sewage into water bodies contaminates the freshwater resources of the earth. When sewage is released into freshwater bodies like lakes and rivers, freshwater gets contaminated with infectious organisms and makes the water unfit for consumption. Most of the rivers of the earth are getting polluted, which also disturbs the ecosystem of water bodies. Farmers are using insecticides and pesticides, which come down with rainwater and pollute the groundwater. Water of rivers is unfit for drinking purposes, therefore, water scarcity problems are common in many big cities.
4. How much area of India is under forest cover?
Answer: At present, India has 23% of its land covered under forests.
5. What is the enrichment of minerals?
Answer: The enrichment of minerals refers to the process by which the concentration of valuable minerals in an ore is increased through various physical or chemical methods. (This answer is not there in the textbook)
6. List two uses of coal.
Answer: The two uses of coal are:
- Major use of coal is to generate power. When coal is burnt, it generates heat, and this heat is used to convert water into electricity. Steam pressure helps rotate the turbine, thus generating electricity.
- Coal is also used in the steel industry. It is first heated to convert it into coke, which is almost pure carbon. A mixture is made of iron ore, coke, and limestone, which is heated to make iron.
7. Man’s dependence on petroleum is increasing. Explain.
Answer: Petroleum is used as a fuel and as raw material in various chemical industries. The dependence of the human population on petroleum and its products is increasing day by day. Increasing population pressure has led to enormous demand for this fuel. The reservoirs beneath the surface of the earth have started going down.
8. What is the composition of natural gas?
Answer: Natural gas is also a fossil fuel made up of hydrocarbons. Its major constituents are methane (85%) and ethane (10%). Its major impurities are nitrogen, carbon dioxide, and hydrogen sulfide, which are removed during the process of refining.
9. Give two uses of natural gas.
Answer: The two uses of natural gas are:
- It is used as fuel for heating, cooking, and generating electricity.
- It is also used in kilns to bake bricks and ceramic tiles. Cement is also manufactured with its help as a fuel.
10. How is natural gas transported?
Answer: During earlier times, it was not possible to transport gas because it could not be stored. In the 19th century, it was treated as a waste by-product of petroleum. Later, technology was developed to liquefy it and transport it.
Long Answer Questions
1. What are the main sources of air pollution? Name two air pollutants.
Answer: Various human activities like transportation, industrialization, and agriculture release numerous pollutants that change the composition of air. Air pollution is more severe in urban areas compared to rural areas. Maximum pollution can be seen in the industrial areas of the cities.
Major pollutants of air are sulphur dioxide, nitrogen oxide, carbon dioxide, fly ash, and suspended particulate matter (SPM). Smog is often seen in big cities, which is a smoky mixture of carbon monoxide and organic compounds due to the incomplete burning of fossil fuels. Nowadays, another pollutant called CFC (chlorofluorocarbons) is added to the air. It is a chemical used in spray cans and refrigeration and causes depletion of the ozone layer.
2. Discuss the various uses of air.
Answer: Air is a mixture of gases around any celestial body. The gravitational pull of that celestial body prevents the gases or air from escaping. Our earth has gravitational pull; therefore, the air remains attached to it.
Uses of air:
- Oxygen is the most important of all the gases as it is a life-supporting gas for all organisms.
- Nitrogen is the largest constituent. It is chemically inactive and acts as a diluent.
- Carbon dioxide is used for the process of photosynthesis, therefore, required by all green plants. It also absorbs the radiant energy of the earth and re-radiates it back to the earth. Therefore, it is also called a greenhouse gas. It increases the temperature of the lower atmosphere.
- Ozone gas absorbs the ultraviolet rays of the sun and thus prevents the earth from becoming too hot. Its other uses are water purifying, bleaching food, and sterilizing air.
- Water vapors become heavy on cooling. Dust particles help in bringing rainfall because when water vapors become heavy after cooling, they deposit on dust particles.
3. What is the difference between evaporation and condensation?
Answer: Evaporation is the process where a liquid turns into a gas or vapor due to an increase in temperature or exposure to air, typically occurring at the surface of the liquid. Condensation, on the other hand, is the process where a gas or vapor cools down and changes back into a liquid, usually when it comes into contact with a cooler surface or environment. (This answer is not there in the textbook)
4. Explain the various uses of water.
Answer: Water is an essential resource for life on the planet Earth. No organism can function without water. It is also a major constituent of living matter, with 50 to 90% of the weight of living organisms being water. Around 71% of the Earth’s surface is covered with water, but 97% of this water is contained in the oceans and is saline, making it unsuitable for direct use. Freshwater, which is found in rivers, glaciers, groundwater, and lakes, is the only usable form. Rain is the ultimate source of all freshwater. The level of groundwater is continuously falling due to deforestation and excessive irrigation. Efforts should be made to recharge groundwater through watershed management.
Uses of water:
- Among the various gifts of nature to man, water is a precious one. Apart from giving life to all organisms, it is also a raw material for many industries.
- It can dissolve most substances, making it useful for diluting and removing waste.
- When water is made to fall on turbines, it generates hydel power, which is used as energy in the fast-developing world. The method of power generation through water is a pollution-free method.
- Water, being a cheap means of transport, is widely used in international trade.
Present status of water:
- With time, the availability of freshwater is decreasing.
- There are limited reserves of freshwater, and they are getting polluted.
- Discharge of municipal and industrial sewage into water bodies contaminates Earth’s freshwater resources.
- When sewage is released into freshwater bodies like lakes and rivers, freshwater gets contaminated with infectious organisms, making it unfit for consumption.
- Most of the rivers on Earth are getting polluted, disturbing the ecosystem of water bodies.
- Aquatic life is exposed to danger.
- Farmers use insecticides and pesticides, which come down with rainwater and pollute groundwater.
- The water of rivers is unfit for drinking purposes, leading to water scarcity problems in many big cities.
5. Discuss the composition of soil.
Answer: Soil supports all plant life of the earth’s crust. The nature and amount of plant life depend upon the soil of that area. It acts as a storage reservoir for water and other plant nutrients. The loose material of soil consists of organic and inorganic material. The inorganic material is derived from the rocks that have broken down by various means. The organic material is derived from the debris of plants and other life forms like microorganisms. Inorganic matter and organic matter make up 50% of the volume of soil. The remaining 50% is pore space, which is the open space between the soil particles. It allows water and air to move in the soil.
Humus is an odourless, amorphous, homogeneous dark-colored material. The end products of its decomposition are carbon dioxide, ammonia, and mineral salts.
6. Do modern agricultural activities pollute the soil? How?
Answer: Soil pollution is the building-up of toxic compounds or pollutants in the soil. It affects the plant and animal life in the soil. Pathogens or disease-causing organisms also develop in the soil. Farmers treat the soil with fertilizers, insecticides, pesticides, fungicides, herbicides, etc., which disturb the growth of bacteria, fungi, and other organisms. The formation of humus stops. Dumping of industrial and municipal wastes also spoils the soil condition. Many pollutants are released from these wastes that contaminate the soil.
7. Describe the various uses of forests.
Answer: Forests provide habitat to numerous species of plants and animals. All inhabitants get food and protection from the forests. They help in protecting the soil from erosion. Forests store a large amount of water, which acts as a buffer for the ecosystem during dry periods. They play a vital role in atmospheric circulation and thus control the global climate. The leaves of trees absorb carbon dioxide and release oxygen, a phenomenon that is vital for all life on Earth. Forests provide timber to humans for various activities like construction. They are a source of edible fruits and nuts. Numerous waxes and oils are also obtained from forests. The sap of many trees is used as a raw material to manufacture a variety of goods. The bark of some trees is used to make cork and medicines. A variety of chemicals are procured from forests for use in tanning leather, inks, dyes, medicines, alcohol, etc.
8. Differentiate between coal and coke.
Answer: Coal is the largest conventional fossil fuel. It is a combustible organic rock composed of carbon, oxygen, and hydrogen. It was formed in the Carboniferous period (360 million–290 million years ago) when plants died, decomposed, and remained buried in the earth’s crust. Continuous heat and weight converted this matter into coal. Coal is rich in hydrocarbons and is also called a fossil fuel.
Coke is almost pure carbon and is produced by heating coal. It is used in the steel industry. A mixture of iron ore, coke, and limestone is heated to make iron. During the process of coke formation, various types of gases are released, which are used in industries like fertilizer, pesticide, and medicine.
9. Describe the major uses of natural gas.
Answer: Natural gas is a major source of energy. It is used in industries for heating and power generation. It is also used in kilns to bake bricks and ceramic tiles. Cement is also manufactured with its help as a fuel. Other uses of gas as fuel include glass making, food processing, and making steam in water boilers. Natural gas is also used as a raw material in industries. As a raw material, its major use is in the manufacturing of petrochemicals. These chemicals are derived from gas and petroleum. Petrochemicals are used in fertilizers, medicines, detergents, plastics, etc.
Extras
Additional questions and answers
1. Define natural resources?
Answer : Natural resources are the components of the natural environment that can be drawn upon for the benefits of human beings. Any component of the natural environment which can be drawn upon for the survival, development, and prosperity of human beings is called a natural resource.
46. Why is natural gas considered an important energy source?
Answer : Natural gas is considered an important energy source because it is a fossil fuel made up of hydrocarbons, with its major constituents being methane (85%) and ethane (10%). It is used as a fuel in various applications such as running machinery, auto-vehicles, kilns for baking bricks and ceramic tiles, cement manufacturing, glass making, food processing, and generating steam in water boilers. Additionally, it serves as a raw material in industries, particularly for manufacturing petrochemicals, which are used in fertilizers, medicines, detergents, plastics, and more.
Additional MCQs
1. Natural resources become resources only when they are:
A. Found in nature
B. Used by humans
C. Inexhaustible
D. Renewable
Answer: B. Used by humans
31. The process of extracting minerals from the earth is known as:
A. Drilling
B. Mining
C. Excavating
D. Refining
Answer: B. Mining
Ron’e Dutta is a journalist, teacher, aspiring novelist, and blogger who manages Online Free Notes. An avid reader of Victorian literature, his favourite book is Wuthering Heights by Emily Brontë. He dreams of travelling the world. You can connect with him on social media. He does personal writing on ronism.
Get notes of other boards, classes, and subjects
| Notify change in syllabus/books | Share PDFs of books, get benefits |
| Request notes not available now | Share PDFs of question papers |