The circulatory system is system in the human body that provides a network through which our blood flows constantly.The human cardiovascular system is considered closed because there are no holes for blood to enter or leave the system. Correct answer: D
In the closed circulatory system the blood stays confined within the vessels and heart.
A lack of Vitamin C may lead to scurvy
9. A villa
10. C ascending colon
11. A. Gastric acid