$GABA$ (Gamma-aminobutyric acid) is a:

What is the primary function of acetylcholine?

In $P$,the membranes of pre-synaptic and post-synaptic neurons are in very close proximity,whereas in $Q$,there is a space between the membranes of pre-synaptic and post-synaptic neurons.
$\quad\quad\quad P\quad\quad\quad Q$

The chemical causing the transmission of nerve impulse across synapses is

The figure shows an axon terminal and synapse. Select the option giving correct identification of labels $A-D$.

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