Final answer:
When a macrophage engulfs a virus, this is an example of phagocytosis, the process by which a cell takes in and destroys large particles.
Step-by-step explanation:
When one cell engulfs another cell, like when a macrophage engulfs a virus, this is an example of phagocytosis, which is the process by which a cell takes in large particles or other cells. In this case, the macrophage surrounds and engulfs the virus, which is then destroyed by the lysosomes inside the macrophage.