apoptosis: a type of cell death in which the cell uses specialized cellular machinery to kill itself; a cell suicide mechanism that enables metazoans to control cell number and eliminate cells that threaten the animal's survival
physical entity: an entity that has physical existence
kaffir boom: small semi-evergreen broad-spreading tree of eastern South Africa with orange-scarlet flowers and small coral-red seeds; yields a light soft wood used for fence posts or shingles