Is the primary neurotransmitter secreted by motor axons of the cns.

The correct answer is acetylcholine.

Acetylcholine is the primary neurotransmitter in motor neurons and actually the most abundant neurotransmitter in the human body. In motor neurons, it functions to open sodium channels in the neuromuscular junction therefore depolarizing the muscle cell membrane and exhibiting an action potential that will eventually activate muscle excitation-contraction coupling.