31.
Heavy metal pollution of water is caused by:

32.
Ozone layer in the upper parts of the atmosphere serves as a protective shield against harmful

33.
'Bhopal gas tragedy' 1984 is related to which gas

34.
When a nutrient like fertilizer is present in large quantities in a water bodies, plants grow and decay in large numbers because of suffocation of pond that does not leave enough oxygen needed to support life. This type of pollution is called

35.
Which of the following is the correct sequence of countries in terms of maximum carbon dioxide emission?

36.
The function of skimming tank in sewage treatment is to remove

37.
Acid rain is caused due to emission of which of the following into the atmosphere ?

38.
The depletion of Ozone layer is mainly due to

39.
Chemical name of vinegar is

40.
Which one of the following organic compounds has fruity smell?