What cellular process involves the fusion of the plasma membrane with vesicles?

The correct option pertains to exocytosis, a vital cellular process where vesicles within the cell fuse with the plasma membrane to release their contents outside the cell. This mechanism is crucial for a variety of functions, including the secretion of hormones and neurotransmitters, the expulsion of waste materials, and the delivery of membrane proteins. When a vesicle approaches the plasma membrane, specific proteins help facilitate the fusion, allowing the materials packaged within the vesicle to spill into the extracellular environment. This process is significant for maintaining cellular homeostasis and communication.

The other processes listed do not involve the fusion of the plasma membrane with vesicles in the same manner. Endocytosis involves the inward folding of the plasma membrane to engulf external substances, cell division refers to the process of a cell replicating and splitting into two, and replication is specific to the copying of DNA during cell division.