Final answer:
Exocytosis is the process by which secretory vesicles release their contents to the cell's exterior. It occurs when vesicles fuse with the plasma membrane and their contents are released outside the cell. Neurotransmitter release at synapses is an example of exocytosis.
Step-by-step explanation:
Exocytosis is the process by which secretory vesicles release their contents to the cell's exterior. During exocytosis, vesicles containing substances fuse with the plasma membrane and their contents are then released to the exterior of the cell. This process is usually triggered by a release of neurotransmitters, which is an example of exocytosis that occurs at synapses between neurons.