Answer:
Basically, it alerts you when it senses something wrong either on the inside or outside so you can react to it. For example, if you had your hand on a hot stove and didn't have your nervous system, you wouldn't know and your hand would burn. But with your nervous system, you feel pain and immediately take your hand off.
Step-by-step explanation:
"Within the process of homeostasis the nervous system detects and responds to adaptions within the body's internal and external environments by sending fast electrical impulses through nerves to the brain which instructs an effector and enables them to react quickly and return the body to a state of equilibrium."