Answer:
Parkinson's disease is to dopamine as depression is to serotonin.
Step-by-step explanation:
Serotonin is often described as a chemical that brings happiness in a person. Low levels of serotonin can cause depression and sad moods in a person. Serotonin is known to enhance the mood of a person by suppressing the depressive thoughts.
Parkinson's can be described as a degenerative disease of the body. Parkinson's disease has no cure up till now but the condition of the person can be made better by dopamine.