Which system is responsible for converting food into energy and transporting nutrients?

Which system is responsible for converting food into energy and transporting nutrients?

• A. Circulatory system
• B. Nervous system
• C. Digestive system
• D. Immune system

Answer: (C)

The digestive system is responsible for turning the food you eat into energy‑rich molecules and making nutrients available to the body. It breaks down carbohydrates into glucose, proteins into amino acids, and fats into fatty acids and glycerol. Those smaller molecules are then absorbed through the lining of the small intestine into the bloodstream, where they can be transported to cells for energy and growth. Once absorbed, the circulatory system handles moving these nutrients to all body tissues, but the actual conversion and initial absorption occur in the digestive system. The other systems don’t perform both roles: the circulatory system mainly transports substances around the body, the nervous system coordinates activities, and the immune system defends against pathogens.

The digestive system is responsible for turning the food you eat into energy‑rich molecules and making nutrients available to the body. It breaks down carbohydrates into glucose, proteins into amino acids, and fats into fatty acids and glycerol. Those smaller molecules are then absorbed through the lining of the small intestine into the bloodstream, where they can be transported to cells for energy and growth. Once absorbed, the circulatory system handles moving these nutrients to all body tissues, but the actual conversion and initial absorption occur in the digestive system.

The other systems don’t perform both roles: the circulatory system mainly transports substances around the body, the nervous system coordinates activities, and the immune system defends against pathogens.