What are the two main components of the cardiovascular system?

The cardiovascular system is primarily composed of the heart and blood vessels, which work together to circulate blood throughout the body. The heart is the muscular organ that pumps blood, ensuring it flows to various tissues and organs to deliver oxygen and nutrients while removing carbon dioxide and waste products. Blood vessels, which include arteries, veins, and capillaries, form a complex network that facilitates this circulation.

Arteries carry oxygen-rich blood away from the heart, while veins return oxygen-poor blood back to the heart. Capillaries, the smallest blood vessels, allow for the exchange of oxygen, nutrients, and waste products at the cellular level. Together, the heart and blood vessels create a continuous loop, making them the core components of the cardiovascular system.

Other options, such as the brain and blood vessels, or the heart and lungs, do not encompass the full scope of the cardiovascular system's primary function, which is to circulate blood. Similarly, while arteries and veins are crucial parts of the system, they do not represent the entire cardiovascular structure without considering the heart’s role as the central pump driving circulation.