Chapter 1 Natural Resources
Natural Resources – Air, Water and Land
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1. What are the five layers of the atmosphere?
2. What would have happened if there were no air on the earth?
3. In what ways is the water in seas and oceans useful even though it is salty?
4. Do other living things use water like we do?
5. What is land made of?
6. Is land flat everywhere?
7. What do you see on land?
8. Does man produce soil/land?
9. What has man created on land?
10. If a deep pit is dug in the ground, what do you find there?
11. What are the constituents of soil? Classify them as biotic and abiotic constituents.
Exercise
1. Fill in the blanks.
(a) The layer of ozone gas absorbs __________rays that come from the sun to the earth.
(b) Of the total water available on the earth, fresh water forms __________ percent.
(c) Both __________ and __________ constituents are present in the soil.
2. Why is it said that – ?
(a) The ozone layer is a protective shell of the earth.
(b) Water is life.
(c) Seawater is useful even though it is not potable.
3. What will happen if –
(a) Microbes in the soil get destroyed.
(b) The number of vehicles and factories in your surroundings increases.
(c) The total supply of potable water is finished.
4. Match the following.
Group ‘A’ Group ‘B’
(1) Carbon dioxide (a) Generation of soil
(2) Oxygen (b) Rain
(3) Water vapour (c) Plants and food production
(4) Microbes (d) Combustion
5. Name the following.
(a) Constituents of the biosphere
(b) Biotic constituents of soil
(c) Fossil fuel
(d) Inert gases in air
(e) Gases that are harmful to the ozone layer
6. True or false?
(a) Land and soil are the same thing.
(b) The water in a lake is called ground water.
(c) It takes about 1000 years to form a 25 cm thick layer of soil.
(d) Radon is used in decorative lights.
7. Answer in your own words.
(a) Explain with the help of a diagram how soil is formed.
(b) Why is there a shortage of water even though it occupies about 71% of the earth’s surface?
(c) What are the various constituents of air? Write their uses.
(d) Why are air, water and land considered to be valuable natural resources?
Air, water and land are the factors important for sustaining the living world on the earth and for fulfilling their basic needs. Therefore, they are considered to be natural resources.
Fill in the blanks.
1. Air, water and land are called the earth’s __________, __________ and __________, respectively.
2. These living things and the parts of the lithosphere, hydrosphere and atmosphere which they occupy are together called the __________.
3. The __________ is the layer of air that surrounds the earth.
4. The surface of the earth comprises water and land, that is, the __________ and __________.
5. The __________ contains about 80% of the total mass of gases in the air, while this proportion is about 19% in the __________.
6. In the mesosphere and ionosphere, the proportion of the mass of gases goes on __________.
7. Gases are not found in the __________ and beyond.
8. The amount of the gases in the air is the __________ near the surface and __________ as we go higher and higher from the surface.
9. Air becomes __________ at higher altitudes.
10. __________ helps living things to build the necessary proteins.
11. __________ is useful in the production of ammonia and in airtight packaging of foodstuffs.
12. __________ necessary for respiration in living things and for combustion.
13. __________ necessary for combustion.
14. Plants use __________for producing their food.
15. __________is used in fire extinguishers.
16. __________ used in electric bulbs.
17. __________ used for obtaining low temperature and also for generating lift in airships.
18. __________ used in decorative lights and for street lighting.
19. __________ used in fluorescent tubes.
20. __________ used in flash photography.
21. It is in the __________ that fog, clouds, snow and rain are produced.
22. There is a layer of __________ gas in the lower part of stratosphere.
23. The ozone gas absorbs the __________ rays.
24. The ozone layer is destroyed if chemical gases like __________ or the
__________ used in air conditioners and refrigerators mix with the air.
25. __________ is celebrated as ‘Ozone Protection Day’ all over the world to make everyone aware of the importance of ozone.
26. We need to drink __________ litres of water every day so that all our bodily functions run smoothly.
27. If __________ gas burns in air, it combines with oxygen and water is formed.
28. In nature, water occurs in three states, solid, liquid and gaseous.
29. __________ does not have colour, taste or odour.
30. Many substances readily dissolve in water. Therefore, water is a universal solvent.
31. The ________________ formed from oceans is the main source of water in the
water cycle.
32. All __________ animals including man live on land.
33. The __________ components of soil are supplied through the weathering of the bedrock.
34. It takes about a thousand years for a __________ thick layer of mature soil to form.
35. __________ of land is reduced if grass, trees and bushes are grown in it.
36. __________ is the layer formed on soil due to the decomposition of dead plants and animals
by microbes.
37. __________ supplies nutrients to the soil.
38. Humus is also important for __________ the soil and for holding water in the soil.
39. The proportion of humus in the upper layer of good fertile soil is about __________.
40. We get fuels like petrol, diesel, kerosene, paraffin and other useful materials like tar and wax from the fossil fuel called __________.
41. The elements available in nature which fulfil the basic needs of living things are called __________.
42. Air, water and land are important __________.
43. The __________ layer is a protective shell of the earth.
44. ______________ should be used carefully and sparingly.
Answer the following questions
1. What are natural resources?
2. Name the three spheres of the earth.
3. What is the proportion of land and water on the earth?
4. Name the components of atmosphere and their proportion.
5. Why is atmosphere very important?
6. What is air pollution?
7. How is air pollution increasing?
8. Write a note on ozone layer.
9. Why is ozone layer called the protective shell?
11. Why are large pollution boards displayed in metropolitan cities?
12. Write the properties of water.
13. Why is it said that water is life?
14. How do we get rain?
15. Name the different ways of conserving water.
16. How is land an important resource?
17. Name the layers of soil formed under the earth.
18. What is the best remedy for conserving and preventing soil erosion?
19. Write a short note on humus.
20. Write a short note on fossil fuel.
21. Write a short note on India Meteorological Department (IMD)
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For answers click on the link – Answers