Question

what is the role of immune system when a disease causing microbes enters the healthy human body

Answer 1

When a disease causing microbe enters in our body,the good microbes present in the immune system fights those bad microbes so that they do not damage our immune system and weaken our body.

Answer 2

Immune system is mainly the defense mechanism of our body.
Various bacteria, fungi, virus, etc. attacks our body.
Immune system detects these foreign invaders & provide us protection. It is composed of different cells & proteins which fight with different germs & microbes.