Question

which structure stores neurotransmitters at the terminal? astrocytes axon hillock tracts synaptic vesicles

Explanation:

Astrocytes are glial cells that support neurons, not store neurotransmitters. The axon hillock is where action potentials initiate. Tracts are bundles of axons in the central nervous system. Synaptic vesicles are small sacs located at the axon terminal that hold neurotransmitters until they are released into the synapse.

Answer:

Synaptic vesicles