I.What organ propels blood through the blood vessels?

A.brain. B.blood vessels C.heart

2.Wich of the following bones protects the heart and lung?

A.backbone B.rib cage C.skull

3.Why are valves important in the heart and blood vessel?

A.the valves keep the blood flowing.

B.The valves keep the blood oxygenated.

C.The valves prevent the black flow of the blood.

4.Wich of the following statements is/are true about the heart?

I. The heart is a muscular organ

II. The heart pumps the blood throughout the body .

III.The heart is about the size of a clenched fist.

IV. heart warms the blood before it goes to the lungs.

A.I and II only B.II and III only C.I, II and III only

5.What is the main breathing organ of the body that filters and purifies air that gets inside our body?

A.lung B.mouth C.valves​