You are presented with the question "What occurs in response to a change in the environment?" and the following answer choices: 
- relocation
 - sunlight
 - moonlight
 - artificial selection
 - ground to shake
 - Animal survival
 - natural selection
 - It helps them survive

Now knowing that evolution occurs in response to a change in the environment and natural selection is the main mechanism of evolution, choose the best answer.


 

       natural selection  