Answer:
Positive reinforcement.
Explanation:
Positive reinforcement is a method in psychology, that refers to the introduction of a <em>desirable or pleasant stimulus after the behavior.</em>
Desirable stimulus reinforces the behavior, which makes it more likely that the behavior will reoccur in the future.
In this case, Joe's boss allowed him to leave early because he did a good job that day, so he got to finish his shift early and enjoy his free time. His boss is hoping that he will continue to do good work due to his generous act.
The answer is A, the immune system
True.
Exercise can lower levels of estrogen in the blood.
