Final answer:
Acetylcholine is the neurotransmitter that stimulates skeletal muscle contraction at the neuromuscular junction.
Step-by-step explanation:
The neurotransmitter acetylcholine stimulates skeletal muscle contraction. It is released by nerves at the neuromuscular junction, which is a specialized synaptic structure where the motor neuron connects with the muscle fiber. When acetylcholine binds to receptors on the muscle fiber, it initiates a muscle contraction.
Acetylcholine (ACh) is a neurotransmitter, which is a chemical messenger that transmits signals across synapses, the junctions between neurons or between neurons and muscles. Acetylcholine plays a crucial role in the central nervous system (CNS) and the peripheral nervous system (PNS) and is involved in various physiological processes.