Question

What does an antioxidant do for the human body? Use the Internet or a book to answer this.
Complete this equation. H2O2 -----------------------> _____________ + ____________

Answer 1

An antioxidant neutralizes free radicals. It breaks the chain of the free radical so for your equation pick the structure for say vita E (an antioxidant) and allow it to break the H2O2 into H2O and H

Answer 2

You first need to think of what "antioxidant" means, an oxidant is something that, you guessed snatches electrons from things in a reaction (if you didn't guess it then review redox reactions).
An antioxidant is therefore something that gets rid of those oxidants.
There is this cool thing in our body called oxygen, but sometimes, oxygen screws us up and kills us by being in a reactive form (superoxide if you are interested). Now if we didn't have something in our bodies, this reactive form of oxygen would force us to live in an anaerobic environment (without oxygen). Fortunately we have this cool thing called superoxide dismutase which converts this reactive oxygen into hydrogen peroxide and regular oxygen. This makes our bodies happy.
Unfortunately hydrogen peroxide is toxic so we need another enzyme, by the name of catalase, to convert hydrogen peroxide into oxygen and water. Our body is then happier than it was before.

Without both of these an organism is a strict anaerobe. With the first then it is a facultative aerobe and with both it is an aerobe.

So the answer, after tons of explanation that you can use to wow your friends and teacher.
H2O2----Catalase--->H2O+O2