why do we have blood in are body?

Cuz its cool!

It carries nutrients to other places in your body, heals your scratches and cut and such, and because... I might as well not say that... Well, why not?
SO THAT WE CAN MAKE MOVIES BLOODY AND GOREY!!!!!!! IT HELPS IN A LOT OF HORROR MOVIES!!! YAYZ!!!

To carry oxygen and other important nutrients, wastes, and the like around your body. That's essentially what blood does.

Duh. So when we get cut, our skin heals

So the vampires can have something to drink, duhhh

to keep our muscles working so we can move!

i think u should ask that to 'your_creepy_science_teacher'