Which of the following is not a greenhouse gas?

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

$(a)$ Where is the ozone layer found?
$(b)$ What is an ozone hole and how is it caused?
$(c)$ State the harmful effects of ozone depletion.

How is acid rain caused?

$(a)$ Study the given figure of the nitrogen cycle and mention what $A, B, C, D,$ and $E$ represent.
$(b)$ What will happen if step $A$ does not occur?
$(c)$ Write the role of nitrogen-fixing bacteria in the biosphere.
$(d)$ Name two biologically important compounds that contain both $O_2$ and $N_2$.

How is the life of organisms living in water affected when water gets polluted?