On the Web For more on programmed cell death: www.celldeath.de/ encyclo/aporev/aporev.htm http://users.rcn.com/jkimball.ma. ultranet/ BiologyPages/A/ Apoptosis.html

WASHINGTON - In an act of ultimate self-sacrifice, millions of human cells commit suicide every day, making your life better by their death. Some cells kill themselves so that developing embryos don't grow webs between their fingers and toes. In teenagers, unused brain cells are pruned away. Other cells kill themselves after damage by radiation or smoking.