Science 6 Reviewer

It is the complete trip of the blood from the heart to all parts of the body and back to the heart.

• digestion

• circulation

• respiration

• secretion

Answer explanation

The movement of blood from the heart to the body and back is the key function of the circulatory system.

Let us evaluate the options.

*Digestion: This refer to the breakdown of food into nutrients not related to the blood movement.

*Circulation: This refers to the movement of blood throughout the body, which matches the description given.

*Respiration: This involves the exchange of gasses oxygen and carbon dioxide; not the blood flow.

Secretion: This refers to the release of substances from cells not related to the blood circulation.

What happens to the blood when it reaches the lungs?

• The blood becomes pure red.

• The blood becomes oxygenated in the lungs.

• The blood becomes deoxygenated in the lungs.

• The blood flows continuously to the body.

Answer explanation

In the lungs, the blood undergoes gas exchange. The oxygen from the inhaled air diffuses into the blood, while the carbon dioxide diffuses out of the blood into the lungs to be exhaled.

What makes the blood flow through the blood tubes?

• The blood becomes oxygenated in the lungs.

• The blood does the circular movement.

• The heart pumps blood to the different parts of the body.

• The heart has two ventricles for pumping blood.

Answer explanation

The question asks about the force that drives blood circulation.

Let us evaluate the options:

1. 1.The blood becomes oxygenated in the lungs.

2. -this describes the process of oxygenation, not the force behind the blood flow.

2.The blood does the circular movement.

-This describes the circulatory system's function but doesn't explain the driving force behind the movement.

3.The heart pumps blood to the different parts of the body.

-This directly indicates the action that propels blood through the circulatory system.

4.The heart has two ventricles for pumping blood.

-While this is true, it does not explain the overall process of blood flow.

Study the diagram. Which part of heart that contracts and pumps the blood containing rich oxygen to all parts of the body.

• 2

• 3

• 6

• 7

Answer explanation

The left ventricle is the chamber of the heart that pumps oxygen-rich blood to the body. The left ventricle is labeled as number 6 in the diagram.

Study the diagram. Which part of the heart that contracts and forces the blood out of the heart to the lungs?

• 7

• 6

• 3

• 2

Answer explanation

The right ventricle is the chamber of the heart that pumps deoxygenated blood to the lungs. The right ventricle is labeled as number 3

Which of the following controls our body activities?

• nerves

• spinal cord

• brain

• backbone

Answer explanation

Brain is the control center of the body, responsible for processing information and coordinating activities.

Which of the following carries/carry messages to and from the brain?

• nerves

• spinal cord

• vertebrae

• backbone

Answer explanation

Nerves are the basic unit of the nervous system, responsible for carrying messages.

Why can you hear sounds?

• The nerves that are sensitive to the sound carry the message to the brain.

• The nerves that are sensitive to the light carry the message to the brain.

• The outer ear collects sounds.

• The sounds are loud enough.

Answer explanation

The nerves that are sensitive to the sound carry the message to the brain because of the auditory nerve that connects the ear and the brain. The auditory nerve carry the message to the brain.

The action that happen without thinking about it is ____________.

• receive action

• reflex action

• retract action

• reverse action

Answer explanation

A reflex action is an automatic response to a stimulus, happening without conscious thought.

What is the function of the spinal cord?

• Responsible for man's ability to learn habits and develop skills.

• Enables us to think, learn, remember and be aware of many things around us.

• Enables the sensory and motor information to pass between the brain and the parts of the body.

• Carry impulses from sense receptors to the central nervous system.

Answer explanation

The spinal cord is the major component of the central nervous system, responsible for transmitting signals between the brain and the rest of the body. It enables sensory and motor information to pass between the brain and the parts of the body.