Suppose the terminal ends of an axon are in contact with the dendrites of four adjacent neurons,the nerve impulse of the axon will

Explain:
$(1)$ Electrical Synapse
$(2)$ Chemical Synapse

$A$ : Transmission of the nerve impulse across a synapse is accomplished by neurotransmitters.
$R$ : Transmission across a synapse usually requires neurotransmitters because there is a small space,$i.e.$,synaptic cleft,that separates one neuron from another.

Parkinson's disease (characterized by tremors and progressive rigidity of limbs) is caused by the degeneration of brain neurons that are involved in movement control and make use of the neurotransmitter:

What is the primary function of acetylcholine?

Which of the following statements is correct regarding electrical synapses?
$I.$ Pre and postsynaptic membranes are in very close proximity at electrical synapses.
$II.$ Electric currents are involved in the transmission of impulses.
$III.$ Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon.
$IV.$ Impulse transmission is always faster in electrical synapses than across chemical synapses.
$V.$ Electrical synapses are rare in our system.
The correct option is: