Multiple choice

What is the immune system’s first line of defense?

  1. Skin

  2. Macrophages

  3. Dendrites

  4. Neutrophils
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The skin acts as a physical and chemical barrier that prevents pathogens from entering the body, making it the primary first line of defense. Internal immune cells like macrophages, dendrites, and neutrophils act as the second line of defense once pathogens have breached this barrier.

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