What is the body's major defense against "foreign invaders" such as bacteria or viruses?

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Quizplus · Accepted Answer

The immune system is responsible for identifying and eliminating foreign invaders such as bacteria and viruses. It does this through a complex set of mechanisms including identifying and engulfing foreign particles, producing antibodies specific to the invader, and activating immune cells to attack and destroy the invader. The pituitary gland, circulatory system, and central nervous system are important in regulating other bodily functions, but do not play a major role in the body's defense against foreign invaders.

What Is the Body's Major Defense Against "Foreign Invaders" Such