Which body system includes the heart and blood vessels?

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

Answer: (D)

The circulatory system includes the heart and blood vessels, and its main job is to move blood throughout the body. The heart acts as a muscular pump that pushes blood into arteries, which carry it to tissues, where capillaries exchange oxygen, nutrients, and wastes, and then veins return blood back to the heart. This continuous network keeps all organs nourished and helps remove waste.

Endocrine system uses glands and hormones and isn’t defined by the heart or vessels. Nervous system centers on signaling and control with the brain, spinal cord, and nerves. Digestive system handles breaking down food and absorbing nutrients. Each of these has a distinct primary function separate from circulating blood.