Acellular process called is responsible for programmed cell death.

Apoptosis. This is a process of programmed cell death that occurs in various organisms. There biochemical processes that lead to morphological cell changes of the cell. This changes are blebbing, cell shrinkage, nuclear fragmentation. This must be differentiated from necrosis. which is a form of cell death due to acute cellular injury. Apoptosis is a regulated process that serves as an advantage of the organism life cycle. Usually this can be initiated by intrinsic pathway when the cell kill itself when there are cell stressors and extrinsic pathway where death occurs due to signals from other cells. 

Organism, organ system, organs, tissue, cells