One example of this phenomenon is the reabsorption
One example of this phenomenon is the reabsorption of the tadpole tail during metamorphosis in  to a frog, as well as the sloughing off of the inner utering lining. External signals that can trigger it include TNF-alpha and Fas ligand, while damage to the cell can cause Bcl-2 to trigger the release of Apaf-1, which in turn triggers this process. It is also the main process by which the HIV virus destroys T-cells and neurons use a factor protein normally present in mitochondria that induces it instead of capsases. Triggered by the binding of so-called "suicide" proteins, FTP, what is this process of programmed cell death?
One example of this phenomenon is the reabsorption of the tadpole tail during metamorphosis in  to a frog, as well as the sloughing off of the inner utering lining.
apoptosis