Which system controls the heart and blood vessels?

The cardiovascular system is the correct answer because it is primarily responsible for the circulation of blood throughout the body, which includes the heart and blood vessels. This system comprises the heart, which pumps blood, and a network of blood vessels—arteries, veins, and capillaries—that transport blood to and from various tissues. The heart's function is to maintain adequate blood flow to supply oxygen and nutrients to cells while removing carbon dioxide and waste products.

While the nervous system plays a significant role in regulating heart rate and blood vessel tone through autonomic pathways, it does not control the heart and blood vessels directly in the same manner as the cardiovascular system itself. The musculoskeletal system is involved in movement and support, and the respiratory system focuses on gas exchange, neither of which directly governs the functioning of the heart and blood vessels. Thus, the cardiovascular system is the primary system that controls these vital components.