Fact 1: Evolution occurs by a process called natural selection.

Fact 2: Actually, evolution is adaptation to change.

Given the two facts above, answer the question "Changing in animals occurs by a process called what?" with the following options: 
- world climate change
 - It helps them survive
 - natural selection
 - Leptospirosis
 - ozone
 - relocation
 - permineralization
 - animal growth


 

   natural selection      