Development of the nematode Caenorhabditis elegans generates exactly 959 somatic cells; it also produces an additional 131 cells that are later eliminated by apoptosis. Classical genetic experiments in C. elegans isolated mutants that led to the identification of the first genes involved in apoptosis. Of the many mutations affecting apoptosis in the nematode, none have ever been found in the gene for cytochrome c. Why do you suppose that such a central effector molecule in apoptosis was not found in the many genetic screens for “death” genes that have been carried out in C. elegans?