What controls all the activity of the body? How much energy does this organ use?

Think of the brain as a central computer that controls all the body's functions. The rest of the nervous system is like a network that relays messages back and forth from the brain to different parts of the body.

Explanation:

How much energy does the brain require? For the average adult in a resting state, the brain consumes about 20 percent of the body's energy. The brain's primary function — processing and transmitting information through electrical signals — is very, very expensive in terms of energy use.