Answer:
The correct answer is - acetylcholine.
Explanation:
Acetylcholine is a neurotransmitter acts as a chemical message released by nerves to transmit signals from the brain to different parts. It is a chemical compound that is transferred from one nerve cell to others.
An excessive amount of this neurotransmitter acetylcholinesterase is enigmatically degraded by a specific enzyme that changes the structure of the neurotransmitter. This change in the structure results in not able to recognize by the receptor.
Thus, the correct answer is - acetylcholine.