The Immune System: Body Defenders

What You'll Learn

The immune system defends the body against disease-causing germs. White blood cells identify and destroy bacteria and viruses. Vaccines train the immune system to recognize specific threats.

Key Words

nutrients
exercise

Steps

Step 1 — Read

Look at the vocabulary words and write a definition for each in your own words.

Step 2 — Do

Test your peripheral vision: stare straight ahead while a partner slowly moves a colored card from behind your head to the front. Record when you first see the color.

Step 3 — Observe

Draw a detailed diagram of what you observe.

Step 4 — Record

Write a conclusion: what did your results show? Did they match your prediction?

Check Your Understanding

Question 1

1 of 3

What is a reflex?