Define phagocytosis.

Phagocytosis is defined as the process by which a cell engulfs large particles or other cells. This mechanism is a form of endocytosis, whereby the cell membrane wraps around the material to be ingested, forming a vesicle that brings it into the cell. It plays a crucial role in the immune response, allowing immune cells like macrophages to ingest pathogens and dead cells, thereby helping to maintain the body’s homeostasis and defense mechanisms. This is a vital function, enabling the body to eliminate harmful invaders effectively.

The incorrect options refer to different biological processes unrelated to phagocytosis. For instance, the transport of water across a cell membrane pertains to osmosis, while cell division involves processes such as mitosis or meiosis. Similarly, the production of energy in mitochondria relates to cellular respiration and ATP synthesis, both of which are distinct from the act of engulfing particles through phagocytosis.