Which of the following does not act as a neurotransmitter?

The cause of death in a person bitten by a cobra is:

The synaptic knob contains $..........$.

The receptor sites for neurotransmitters are present on ..........

Assertion $(A) :-$ Impulse transmission across an electrical synapse is always faster than that across a chemical synapse.
Reason $(R) :-$ Electrical current can flow directly from one neuron into the other across electrical synapses.

What does the enzyme acetylcholinesterase break down acetylcholine into?