Growth of Lichens on barren rocks is followed by the growth of:

State any two harmful effects each of:
$(a)$ Air pollution,and
$(b)$ Water pollution.

Oxygen is returned to the atmosphere mainly by:

State whether the following statement is true or false:
The process of nitrogen fixation is carried out by bacteria in the presence of oxygen.

State whether the following statement is True or False:
Nitrogen is also found in other biologically important compounds such as alkaloids and urea.

$A$ motor car,with its glass totally closed,is parked directly under the sun. The inside temperature of the car rises very high. Explain why?