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:
The nervous tissue hope it helps :3
B. Food-Borne intoxication I believe is your answer for you my friend
