Final answer:
Apoptosis is a programmed cell death mechanism that occurs in various biological processes, such as amphibian metamorphosis and T-cell development. It is responsible for eliminating unnecessary cells and preventing autoimmune diseases. Apoptosis is also crucial for normal embryological development.
Step-by-step explanation:
Apoptosis is a programmed cell death mechanism that occurs in various biological processes. It is characterized by the controlled and orderly dismantling of a cell, leading to its death. One example of apoptosis is amphibian metamorphosis, where tadpoles digest their own tail cells to grow adult frog structures. Another example is in T-cell development, where immature T-cells that bind to self proteins undergo apoptosis to prevent autoimmune diseases. Apoptosis is also essential for normal embryological development, such as in the formation of separated fingers and toes in vertebrates.