91.
Nitrogen gas returns to the atmosphere by the action of

92.
The most abundant gases in the earth's atmosphere by volume are:

93.
Cigarette smoking exposes one to __________

94.
Of the gases listed below, which is not believed to be responsible for enhancing the earth's greenhouse effect?

95.
The thickness of ozone layer is measured in

96.
Exponential growth occurs when there is

97.
An increase in albedo would be accompanied by ____ in radiative equilibrium temperature.

98.
Many wild plant and animals are on the verge of extinction due to

99.
Most harmful environmental pollutants are

100.
The destruction of the forest areas by man made efforts is called