A brain is the most important part of the human and animalanatomy. In most beings, the brain is located in the head. The brain is what allows us to think, and sends data to the rest of our body so that we can do the things we need to do that are necessary for staying alive. Although most people use only a small percentage of their brain, people with super intelligence use much more. Even people with a genius level intellect use quite a bit of their brain as well.