Final answer:
Acetylcholine is an excitatory neurotransmitter for smooth muscle.
Step-by-step explanation:
An excitatory neurotransmitter for smooth muscle is acetylcholine. Acetylcholine is a chemical messenger that is released by nerve cells to transmit signals to smooth muscles, among other types of muscle fibers. It binds to receptors on the smooth muscle cells and initiates a series of events that lead to muscle contraction.
Learn more about neurotransmitters