31.
At the North Pole the sun will rise above the horizon on ____ and set below the horizon on ____.

32.
World Water Day is celebrated on ___________

33.
A pond, serves as a good example for a __________ water ecosystem.

34.
What is lentic habitat ?

35.
Minamata disease is caused by

36.
The planet with a strong greenhouse effect, whose surface temperature averages 480oC (900oF) is:

38.
Name the disease caused by mercury poisoning in Japan

39.
The Chipko movement is started by

40.
The change of state of ice into water vapour is known as: