Besides the nipple-thing, ever wonder:
My personal favorite (uh-oh, here it comes) is "Why can you light a fart?". No, no - stay with me here. This is very informative (and I quote):
All of this is true, of course, except the part about women farting. How absurd!
Now I do not have time to give you the answers to everything, but like any good teacher, I've given you where to find the answers. Go get 'em, buck-o!