The Immune System
The immune system is a system that works in your body. It may seem like it is nothing but it keeps you healthy and infection-less. It defends your body from microbial infections. The microbial infections are bad for your body. The infections can make you sick. The immune system is very important because if you didnt have the immune system in your body then what would fight off the microbial infections? The immune system keeps your body healthy and fit for you. The immune system plays a very important role for your body. If you didn't have the immune system, your body would be pretty ill right now.
Major Function(s)
The major function that the immune system has is it defends the body from microbial infections. Microbial infections are mini infections that get into your body and the immune system defends the body by fighting the infections off. And keeps you healthy!