Final answer:
Postganglionic sympathetic neurons utilize acetylcholine as a neurotransmitter in sweat glands.
Step-by-step explanation:
The postganglionic sympathetic fibers that contact sweat glands release acetylcholine as a neurotransmitter. This means that sweat glands are innervated by postganglionic sympathetic neurons that utilize acetylcholine as their neurotransmitter.