Question

multiple choice question
how can the human circulatory system be described?
an open system
a closed system
a mixed system (contains one open and one closed circuit)

Explanation:

In a closed - circulatory system, blood is contained within blood vessels and the heart. The human circulatory system has blood that travels through arteries, veins, and capillaries, all connected in a loop, so it is a closed system.

Answer:

B. A closed system