Fact 1: Cancer cells divide more often than normal cells, and grow out of control.

Fact 2: Cancer is an example of a mutation in cells.

Given the two facts above, answer the question "What divide more often than normal cells, and grow out of control?" with the following options: 
- white blood cells
 - Most plants
 - hair cells
 - skin cells
 - Smoking
 - peachleaf willow
 - mutated cells
 - cigarettes


 

       mutated cells  