Your immune system keeps them (INVADERS) away from your healthy cells, protecting you from infections.
How Your Immune System Functions
https://www.medicinenet.com/immune_system_function_immunity_diseases_what_is/article.htm
HE IS RIGHT BUT IR IS ALSO BIGGER THAN THIS
What is first line of defence in immune System
https://www.biologyexams4u.com/2021/06/what-is-first-line-of-defence-in-immune.html
What is Second line of defense in immunology? Defensive cells ...
https://www.biologyexams4u.com/2021/07/what-is-second-line-of-defense-in.html
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