I know, I know, you’re thinking: Duh.

But I saw a guy crush up some iron fortified cereal, put a magnet in it, and pull out iron shards. I guess I never thought about it that way.

Your body needs iron because it is used to carry oxygen through the blood to muscles. But normally when you mix iron and oxygen you get rust. Rust running through your veins would be a bad thing, so that’s why you have hemoglobin.

Hemoglobin is a combination of two separate substances: heme, and globin. Through some combination of these two substances, the iron and oxygen can travel without turning into rust.

It’s all waaaaaaaaaayyyyyy to complicated for a guy who successfully navigated life without ever taking a biology class.

Source: Modern Marvels – Iron

If you have a background in say, chemical engineering, the pages here may make more sense to you.