Exocytosis is a process by which cells:  pass substances out of the cell through the membrane by osmosis.   engulf substances from the extracellular environment.   identify substances in the extracellular environment.   pass substances out of the cell.

Exocytosis is a process by which cells pass substances out of the cell. This process involves the movement of substances from within the cell to the outside of the cell. Here are the steps involved in this process:

1. Packaging: The substances to be exported are packaged into vesicles inside the cell. This is usually done in the Golgi apparatus, a cell organelle responsible for sorting and packaging proteins.

2. Transportation: The vesicle containing the substance moves towards the cell membrane. This movement is facilitated by the cytoskeleton, a network of protein fibers in the cell.

3. Fusion: The vesicle fuses with the cell membrane. This is facilitated by proteins in the vesicle and cell membrane called SNAREs.

4. Release: The substance is released outside the cell. This happens when the vesicle and cell membrane fuse, creating an opening through which the substance can exit.

5. Closure: The cell membrane closes behind the substance, maintaining the integrity of the cell.

So, the correct answer to your question is that exocytosis is a process by which cells pass substances out of the cell.