1. The atmosphere of the Earth is heated by radiations which are mainly

2. If there were no atmosphere around the Earth, the temperature of the Earth will

3. What would happen, if all the oxygen present in the environment is converted to ozone?

4. One of the following factors does not lead to soil formation in nature

5. The two forms of oxygen found in the atmosphere are

6. The process of nitrogen-fixation by bacteria does not take place in the presence of

7. Rainfall patterns depend on

8. Among the given options, which one is not correct for the use of large amount of fertilisers and pesticides?

9. The nitrogen molecules present in air can be converted into nitrates and nitrites by

10. One of the following processes is not a step involved in the water-cycle operating in nature

11. The term “water-pollution” can be defined in several ways. Which of the following statements does not give the correct definition?

12. Which of the following is not a greenhouse gas?

13. Which step is not involved in the carbon-cycle?

14. ‘Ozone-hole’ means

15. Ozone-layer is getting depleted because of

16. Which of the following is a recently originated problem of environment?

17. When we breathe in air, nitrogen also goes inside along with oxygen. What is the fate of this nitrogen?

18. Top-soil contains the following

19. Choose the correct sequences

20. Major source of mineral in soil is the

21. Total Earth’s surface covered by water is

22. Biotic component of the biosphere is not constituted by

23. An increase in carbon dioxide content in the atmosphere would not cause

24. Oxygen is returned to the atmosphere mainly by

25. Oxygen is returned to the atmosphere mainly by

26. Low visibility during cold weather is due to

27. Growth of lichens on barren rocks is followed by the growth of

28. Marked temperature changes in an aquatic environment can affect

29. Soil erosion can be prevented by

30. What happens when rain falls on soil without vegetational cover?

31. Oxygen is harmful for