Which best describes the role of nitrogen in the human body?

A. Makes energy in cells

O

B. Main ingredient of protein

O

C. Makes up 1.5% of the human body

O

D. Transfers energy in cells

B. Main ingredient of protein

Explanation:

Nitrogen is the main element of protein and enzymes in other words, protein and enzymes cannot be formed without nitrogen. This nitrogen is taken by plants from the soil after fixation. Atmospheric nitrogen fixes by nitrogen fixing bacteria and converts it into nitrates. While human take nitrogen by eating animals and plants.