Answer: B.)by consuming plants
Explanation:
There is about 78% nitrogen is available in the atmosphere. But living beings such as plants does not absorb it directly from the air. Instead they absorb the compounds of nitrogen from the soil. The soil bacteria convert the nitrogen oxides into ammonia, nitrates and nitrites in the soil in this way these bacteria fix atmospheric nitrogen into the soil. The plants absorb these forms of nitrogen, which are essentially required for the synthesis of proteins and nucleic acids. Nitrogen as an element becomes essential ingredients in all biomolecules. We humans and animals eat plants and through them the usable form of nitrogen in the form of biomolecules enters the body.
