11- All the following contribute to pollution except

12- Non ionising radiations damaging to DNA are

13- Which insectiside is more hazardous to human health?

14- Effect of pollution is observed first on

15- Biological treatment of water pollution is done with the help of

16- The most common indicator organisms that represents polluted water is

17- As compared to tap water, the BOD of water body polluted with sewage would be

18- Which is more important for water pollution?

19- Which of the following is the main factor of water pollution?

20- Pollution can be controlled by

21- Domestic waste will lead to

22- The major source of BOD in the river Ganga is

23- If a lake is contaminated with DDT, its highest concentration would be found in

24- Sewage water can be purified by

25- BOD is connected with

26- Most important causative pollutant of soil may be

27- Soil erosion occurs due to

28- Removal of the soil by the action of wind and water is known as

29- Spraying of DDT on crops produces pollution of

30- Soil erosion can be prevented by