What are the two main components of the circulatory system and their general functions?

What are the two main components of the circulatory system and their general functions?

• A. The heart (pumps blood) and blood vessels (transports blood to the body).
• B. The brain and nerves.
• C. Lungs (gas exchange) and heart (pumps).
• D. The liver (filters) and kidneys (circulate).

Answer: (A)

Two main components of the circulatory system are the heart and the network of blood vessels. The heart acts as a muscular pump that pushes blood through the vessels, driving the flow that delivers oxygen and nutrients to tissues and carries away waste. The blood vessels form the pathways—the arteries carry blood away from the heart, the veins return it, and the capillaries connect them and enable exchange with body tissues. This pairing explains how blood continuously circulates to sustain the body's needs. The other options mix in parts of other systems or describe functions that aren’t about circulating blood.

Two main components of the circulatory system are the heart and the network of blood vessels. The heart acts as a muscular pump that pushes blood through the vessels, driving the flow that delivers oxygen and nutrients to tissues and carries away waste. The blood vessels form the pathways—the arteries carry blood away from the heart, the veins return it, and the capillaries connect them and enable exchange with body tissues. This pairing explains how blood continuously circulates to sustain the body's needs. The other options mix in parts of other systems or describe functions that aren’t about circulating blood.