Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
What weighs about three pounds and contains up to 100 billion cells? The answer is the human brain. The brain is the control center of the nervous system. It’s like the pilot of a plane. It tells other parts of the nervous system what to do.


Question: Which organ is the control center of the nervous system?
the brain
The brain.