Answer:
Serotonin
Explanation:
Serotonin is often called "happy chemical" because of the important role it plays in emotional well-being and happiness.
It helps, sleep, appetite, digestion, memory, nerve cells, and mood balance. That is why serotonin as a chemical has a connection with depression, though the studies are still trying to determine the exact connection.
Reduced serotonin is also connected with impassivity and aggression
