Apoptosis is a process of programmed cell death. This is a normal process that happens to many
cells such as skin cells which live for only a few weeks and are then sloughed off. Genes suppress
or trigger programmed cell death. Protein cleaving enzymes called ICE-like proteases are signals
that unleash molecular weapons of self-destruction. Cancer cells are abnormal and do not commit
suicide on cue.
This animation (Audio - Important) demonstrates how
apoptosis functions in development.
You are not required to look at this link. However, if you are interested in
apoptosis,
this page has some really good information on the topic.