Fact 1: Cells are programmed to divide only a set number of times.

Fact 2: Apoptosis is programed cell death.

Given the two facts above, answer the question "What kicks in after a certain number of divisions?" with the following options: 
- Energy.
 - antibiotics
 - Energy
 - separation
 - nerves
 - apoptosis
 - soccer leagues
 - Plants growth


 

      apoptosis   