Prefixes:

anti

auto

deca

Examples:

Anti- against 

Antiseptic- against germs

We had to use antiseptic medicine on a cut on my dog.

Antidote- against poison

We had to put an antidote on my cat.

Deca- ten 

Decalogue- 10 commandments

We are all supposed to follow the decalogue.

Decade- 10 years

I have been living for a decade.

Auto- self 

Automatic- by itself

My eyes are automatic when I blink.

Automobile- self running vehicle

My mom and did both drive automobiles.