What are the quick protective reactions that occur within your nervous system called?

They are called reflexes.
Reflexes are quick, protective reactions that occur within your nervous system. They are involuntary actions, meaning that they happen regardless of whether you want them to happen or not. They represent reactions to a certain stimulus. 

Prompt: write about whether or not you plan to register to vote when you are 18 and what political party preference (if any) you will disclose. explain the reasons for your decisions.