Posted by ROSHAN B.S on Aug. 24, 2014, 5:32 p.m.
Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins) and also in the nucleic acids (DNA and RNA). The human body contains about 3% by mass of nitrogen, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into thebiosphere and organic compounds, then back into the atmosphere.