Directions: Choose the letter of the best answer. Write your answers on the blank before the number

1. Why is respiratory system very important to the body?
A. It enables carbon dioxide to get into the body.
B. It consists of body parts that help the body receive oxygen.
C. It helps the blood to circulate in your body.
D. It enables the blood to circulate in your body.

2. How does oxygen in the air get into the blood?
A. through the nose
C. through the mouth
B. through the throat
D. through the tiny capillaries

3. What will happen to the cells of the body when there is absence of oxygen?
A. The cells will continue to grow and multiply.
C. The cells will survive.
B. The cells will be inactive.
D. The cells will die.

4. How can you keep your heart strong?
A. Eating heart-shape candy
B. Doing activities like playing outside, riding your bike, and swimming
C. Smoking
D. Sleeping 18 hours a day

5. What are tubes that carry blood back to the heart?
A. arteries
B. veins
C. pipes
D. tubes

6. Which of the following describes the correct passage of blood originating from the left leg?
A. vena cava - left atrium - right atrium - lungs - left ventricle - right ventride - aorta
B. vena cava right atrium - left atrium - lungs - right ventricle - left ventride - aorta
C. vena cava - left atrium - left ventricle - lungs - right atrium - right ventricle - aorta
D. vena cava - right atrium - right ventricle - lungs - left atrium - left ventricle - aorta

7. What is the functional unit of the nervous system?
A. brain
B. neurons
C. muscles
D. bones

8. What controls and coordinates the activities of the whole nervous system?
A. central nervous system
C. nervous system
B. sympathetic nervous system
D. brain

9. Which of these is not a function of the peripheral nervous system?
A. collects information from the sense organ
B. transmits information to the central nervous system
C. delivers decisions to the body part which will perform the action D. delivers oxygen to the different parts of the body.

10. How do sympathetic and parasympathetic nerves work?

A. When the sympathetic nerve produces an effect, the parasympathetic nerve produces the same effect.
B. When the sympathetic nerve produces an effect, the parasympathetic nerve produces an opposite action.
C. They work separately,
D. They allow messages to pass through them freely.​