Question

The largest reservoir of nitrogen on Earth is

• A. soil
• B. air
• C. oceans
• D. rocks

Answer 1

Answer: (B)

air

Answer 2

Nitrogen is the fourth most prevalent element in living systems. It is available in the atmosphere in abundance ($78\%$ of atmosphere as dinitrogen or $N_2$) but plants cannot directly absorb the same. Nitrogen compounds are obtained from reservoir pool through nitrogen fixation.