C.Directions: Choose the letter of the best answer.

1. Which of the following is NOT a part of the circulatory system?

A. blood B. blood vessels C. brain D. heart

2. Which part of the circulatory system pumps blood to all parts of the body?

A. arteries B. capillaries C. heart D. veins

3. Which blood cells fight foreign substances like virus and bacteria?

A. plasma B. platelets C. red blood cells D. white blood cells

4. Which blood contains most oxygen?

A. the blood that goes to the lungs C. the blood receives by the left atrium

B. the blood coming from the lungs D. the blood pumped by the right ventricle

5. What happens when the blood passes the lungs?

A. The blood becomes red.

B. The blood mixes with carbon dioxide.

C. The blood gives off carbon dioxide and absorbs oxygen.

D. The blood gives off oxygen and carbon dioxide at the same time.

6. Which of the following do you experience when you feel afraid?

A. The heart is rested C. The heart beats slowly.

B. The heart beats faster. D. The heart stops beating.

7. Which chamber of the heart pumps oxygenated blood to all parts of the body?

A. left atrium B. right atrium C. left ventricle D. right ventricle

8. What gives the blood its red color ?

A. carbon dioxide B. cholesterol C. food nutrients D. hemoglobin​