Name the three main components of the circulatory system.

The three main components of the circulatory system are the heart, blood vessels, and blood.

The heart serves as the pump that circulates blood throughout the body, ensuring that oxygen and nutrients are delivered to tissues while also removing waste products. Blood vessels comprise a network of arteries, veins, and capillaries that transport blood between the heart and various parts of the body. Blood, which includes red blood cells, white blood cells, platelets, and plasma, plays a critical role as the medium that carries oxygen, carbon dioxide, nutrients, and waste.

Each of these components is integral to the functioning of the circulatory system and works together to maintain homeostasis and support overall health. The other choices either refer to elements that are part of the respiratory system or specific components of blood rather than encompassing the primary elements of circulation.