producing red blood cells. transporting oxygen to organs. providing nutrients to muscles. controlling the movement of the lungs.
I gave my students this multiple choice question: In the human body, the circulatory system works with the respiratory system by

Only one answer is correct among these 4 choices:
- producing red blood cells.
- transporting oxygen to organs.
- providing nutrients to muscles.
- controlling the movement of the lungs.

Could you tell me which one is correct?

transporting oxygen to organs.