Programmed Aging Theories Propose That Senescence Occurs Because

Programmed aging theories propose that senescence occurs because

A) the telomeres capping the ends of chromosomes become shorter with each cell division and their loss eventually stops the chromosomes from replicating.
B) mistakes in the replication of cells or buildup of damaging by-products from biologic processes eventually destroy the organism.
C) unstable oxygen,formed normally during metabolism,can damage cells by initiating reactions that break down cell membranes.
D) fast-paced living shortens one's lifespan.