What is Apoptosis is: and explain in detail?
Apoptosis: 
Regulated mechanism of cell death that serves to eliminate unwanted and irreparably damaged cells, with the least possible host reaction, characterized by enzymatic degradation of proteins and DNA, initiated by caspases; and by rapid recognition and removal of dead cells by phagocytes.
Kumar V, Abbas AK, Aster JC. Robbins basic pathology. Elsevier Health Sciences; 2017. Page 41