Final answer:
The process by which synaptic vesicles release neurotransmitters is called exocytosis.
Step-by-step explanation:
The process by which synaptic vesicles release neurotransmitters is called exocytosis. When an action potential reaches the axon terminals, voltage-gated Ca²+ channels open and allow Ca²+ ions to enter the cell. The increased concentration of Ca²+ inside the axon terminal triggers the fusion of the vesicles with the presynaptic membrane, resulting in the release of neurotransmitters into the synaptic cleft.