Final answer:
The rewards/pleasure center is a part of the brain and is present in all mammals. It functions to give us pleasure when we satisfy bodily needs, and drugs can be addictive because they stimulate this part of the brain.
Step-by-step explanation:
The rewards/pleasure center is part of the brain and is present in all mammals. It functions to give us a surge of pleasure when we have satisfied some bodily need, such as thirst, hunger, sex, or drugs. The part of the brain responsible for this surge of pleasure is known as the reward/pleasure center. Drugs can be addictive to mammals because they stimulate this part of the brain, leading to the release of chemicals that cause feelings of pleasure.