The human circulatory system
A) uses gravity to move blood to tissues.
B) connects only to the most vital organs in the body.
C) depends on veins to pump the blood through our bodies.
D) is considered a closed system.

Question

Quizplus · Accepted Answer

The human circulatory system is considered a closed system, meaning that blood is continuously cycled through the body and does not interact with the external environment. It relies on the heart to pump blood through a network of arteries, veins, and capillaries to provide oxygen and nutrients to all tissues and organs in the body. While some parts of the system such as valves in veins and muscle contractions can aid in blood flow, gravity alone is not sufficient to move blood throughout the body. Similarly, the system connects to all organs in the body, not just the most vital ones.

The Human Circulatory System