29. The heart is an important organ of circulation ________ function is to pump blood to all parts of the body. A: which B: whose C: of it D: its

12.The function of the cardiovascular<br/>system is to transport blood throughout the body, with the heart acting as the pump for ________. A: circulation B: transportation C: transplant D: operation

（ ） acts as a pump to maintain a constant circulation to blood throughout the body. A: heart B: kidneys C: lungs D: liver

If the _______ stops beating, no blood can flow through the body.() A: heart B: lungs

What are the names for the tubes in your body that carry blood from your heart to the rest of your body.