Answer:
"GFP contained in synaptic vesicles moved into the synaptic cleft by exocytosis."
Explanation:
Synaptic vesicles are small membrane sacs that carry neurotransmitters from the cell body where they are produced, to the presynaptic membrane of the terminal button where they are released. The release zone of the presynaptic membrane contains voltage-dependent calcium channels. When an action potential depolarizes the presynaptic plasma membrane, -channels open, and
flows into the nerve terminal to trigger the exocytosis of synaptic vesicles, thereby releasing their neurotransmitters into the synaptic cleft