Which system includes the heart and blood vessels?

The circulatory system, also known as the cardiovascular system, is responsible for the transportation of blood, nutrients, oxygen, carbon dioxide, and hormones throughout the body. It comprises the heart, which is the pump that propels blood, and a network of blood vessels, including arteries, veins, and capillaries, that facilitate the flow of blood. This system plays a critical role in maintaining homeostasis, supporting immune function, and regulating body temperature by ensuring that all tissues receive adequate blood supply.

The other systems listed do not encompass the heart and blood vessels. The endocrine system is primarily involved in hormone production and regulation of various bodily functions. The reproductive system is focused on the production of gametes and reproductive hormones, while the digestive system is responsible for the breakdown and absorption of nutrients from food. Each of these systems has distinct functions and components, separate from the circulatory system's role in transporting blood and sustaining life.