The energy gave to the body by food is calories
My guess is D. Usually, animals try to scare an assailant and attack as a last resort.
Answer:
You can think of Free radicals as some exhaust from a combustion engine. Get this picture: If an engine is running, it is throwing off some exhaust. Also, if you want to compare this to other things, you can compare it to the human body, as you digest food, breathe, and as you exercise you're producing free radicals. Just by simply living, you are producing them every single second of your life.
Explanation:
