respiratory system circulatory system nervous system skeletal system
I gave my students this multiple choice question: The primary functions of the digestive system are to break down food, absorb nutrients and excrete wastes. Once food is absorbed, what system is responsible for carrying the nutrients to the body cells?

Only one answer is correct among these 4 choices:
- respiratory system
- circulatory system
- nervous system
- skeletal system

Could you tell me which one is correct?

circulatory system