The reproductive organs produce sex cells. The nerves carry signals from the eye to the brain. The bones and muscles of the hand work together to grip a pencil. The muscles of the chest tighten to push carbon dioxide out of the lungs.
I gave my students this multiple choice question: Which best describes two organ systems working together to help maintain homeostasis?

Only one answer is correct among these 4 choices:
- The reproductive organs produce sex cells.
- The nerves carry signals from the eye to the brain.
- The bones and muscles of the hand work together to grip a pencil.
- The muscles of the chest tighten to push carbon dioxide out of the lungs.

Could you tell me which one is correct?

The muscles of the chest tighten to push carbon dioxide out of the lungs.