Correct Option (A)
Apoptosis is a highly regulated and genetically controlled process of programmed cell death that occurs in multicellular organisms. It is essential for various biological processes, including embryonic development (e.g., removal of webbing between digits), maintenance of tissue homeostasis, immune system regulation, and the elimination of damaged, infected, or potentially cancerous cells. Unlike necrosis, apoptosis proceeds without causing an inflammatory response.
Incorrect Options:
2) Ageing: This refers to the progressive accumulation of changes in an organism over time, leading to a decline in physiological functions and increased susceptibility to disease and death. It is a complex biological process, but not a specific mechanism of programmed cell death.
3) Degeneration: This term describes the deterioration of cells, tissues, or organs, leading to a loss of their normal structure and function. While it involves cellular changes and often cell death, it is a broad pathological process and not necessarily a tightly programmed or controlled cellular mechanism like apoptosis.
4) Necrosis: This is a form of uncontrolled cell death that occurs as a result of acute cellular injury, infection, or disease. It is characterized by cell swelling, rupture of the cell membrane, and release of intracellular contents, which typically triggers an inflammatory response in the surrounding tissue. It is distinct from apoptosis, which is a regulated process.