Final answer:
The synapse in the peripheral nervous system formed by terminal boutons is similar to axon varicosities in the central nervous system; the correct answer is A) terminal boutons; axon varicosities.
Step-by-step explanation:
The synapse formed by terminal boutons in the peripheral nervous system are similar in morphology to the axon varicosities in the central nervous system. Therefore, the correct answer to the student's question is A) terminal boutons; axon varicosities. In a chemical synapse, neurotransmitters are released from the terminal boutons of the presynaptic neuron into the synaptic cleft and bind to receptors on the postsynaptic neuron, potentially causing an excitatory or inhibitory postsynaptic potential.
Similarly, axon varicosities in the central nervous system also release neurotransmitters into synapses, though the structure differs slightly. Both entities are involved in synaptic transmission and are essential to communication within the nervous system.