The tremors of Parkinson's disease result from the death of nerve cells that produce the neurotransmitter

A) serotonin.
B) ACh.
C) GABA.
D) dopamine.

Parkinson's disease is caused by the death of nerve cells in a part of the brain called the substantia nigra, which produces dopamine. Dopamine is a neurotransmitter involved in controlling movement and coordination, and a deficiency of dopamine leads to the tremors and other symptoms associated with Parkinson's disease. Treatment often involves administering medications that stimulate dopamine production in the brain or mimic its effects.