The main function of the cardiovascular system is to A. Convert food into simpler substances for the body to absorb nutrients B. Transport blood through the body to supply cells with oxygen and nutrients C. Exchange gases, mostly oxygen and carbon dioxide, between the body and the atmosphere D. Send signals in the form of hormones to the body to control growth, reproduction, and metabolism

B. Transport blood through the body to supply cells with oxygen and nutrients.

Explanation:

Cardiovascular system is a system which include heart, and blood vessels which transport the blood to all the parts of the body. The blood supplies the oxygen and other nutrients to all the parts of the body necessary for the survival of each cell of the body and for the overall body. The heart pumps out oxygenated blood to the body and receives the deoxygenated blood from all the parts of the body for purification.