Nitrogen comprises 78 percent of the atmosphere , the source of this atmospheric nitrogen in due to

Options

A. denitrification by bacteria in the soil
B. combustion of wood and fossil fuels
C. volcanic activity
D. all of the above

Answer

D

Explanation

Nitrogen comprises 78 % of the atmosphere. Denitrification by bacteria results in `NO_3` being broken down into nitrogen and oxygen. Combustion and volcanic activity also play a part in the release of nitrogen to the abnosphere. Nitrogen as `N_2` in the air is, however, of no use to plants. Plants require ions of ammonia (`NH_3`), nitrites (`NO_2`) or the nitrates `(NO_3)` discussed above