Which body system includes the heart and blood vessels?

• A. Respiratory
• B. Nervous
• C. Digestive
• D. Circulatory

Answer: (D)

Identifying which body system contains the heart and blood vessels. The circulatory system, also called the cardiovascular system, includes the heart as the central pump and a vast network of blood vessels—arteries, veins, and capillaries—that move blood throughout the body. This system transports oxygen and nutrients to cells, removes wastes, and helps regulate temperature and immune functions. The respiratory system involves lungs and airways, the nervous system governs signaling and control, and the digestive system handles breaking down and absorbing food. Since only the circulatory system comprises the heart and blood vessels, it is the best fit.