Trying to find the right answer to this..

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

Environmental Issues

Short Answer Type

41. How is air pollution responsible for changing the ill-effects of ultraviolet radiation ?

139 Views

42. Write a note on Biological Oxygen Demand (B.O.D.).

Biological oxygen demand (B.O.D.) represents the amount of dissolved oxygen which is required for bacteria in decomposing the wastes. It is a measure of pollution of water. The BOD test helps to predict a drop in dissolved oxygen levels in natural wastes. Clean water has very low BOD value whereas organically rich water has very high BOD value.

198 Views