Nitrogen is used in respiration to generate energy. Nitrogen is used in making the proteins in the body. Nitrogen is used to help the body eliminate wastes. Nitrogen is used by nerve cells to conduct impulses.
I gave my students this multiple choice question: What is the main reason humans need nitrogen to survive?

Only one answer is correct among these 4 choices:
- Nitrogen is used in respiration to generate energy.
- Nitrogen is used in making the proteins in the body.
- Nitrogen is used to help the body eliminate wastes.
- Nitrogen is used by nerve cells to conduct impulses.

Could you tell me which one is correct?

Nitrogen is used in making the proteins in the body.