In the parasympathetic nervous system,which of the following is released?

Which of the following does not act as a neurotransmitter?

Which of the following is released by the parasympathetic nervous system?

Given below are two statements.
Statement $I$ - In chemical synapse,the rate of transmission of impulse is higher in homeotherms than poikilotherms.
Statement $II$ - In chemical synapse,the synaptic cleft has a width of about $3.8 \ nm$.
In the light of the above statements,select the correct option given below:

Which one of the following does not act as a neurotransmitter?

$A$ nerve impulse is transmitted from one neuron to another through the junctions called