If i had to guess id say B.
Answer: The heart consists of four chambers, two atria (upper chambers) and two ventricles (lower chambers). There is a valve through which blood passes before leaving each chamber of the heart. The valves prevent the backward flow of blood.
Overall health, including weight is directly related to the cardiovascular system. Keeping a healthy weight reduces the amount of sodium in the blood stream, along with other fats. All of these excess nutrients in the blood stream can clog arteries in the cardiovascular system, so staying fit allows all blood pathways in the cardiovascular system to stay clear and keep the heart pumping and healthy.
