Answer: Dopamine
The brain rewards certain activity by releasing dopamine neurotransmitter.
Explanation:
Dopamine is a molecule which is produced naturally by the body. It functions as a neurotransmitter in human brain. It is a chemical released by neurons (nerve cells) to send signals to other nerve cells. It is one of the central power-drivers for all the work of the human brain. It is the key force behind most of human actions and interpersonal relationships.