Fact 1: Mutations are essential for evolution to occur.

Fact 2: Mutations are changes in the DNA sequence.

Given the two facts above, answer the question "What is essential for evolution to occur?" with the following options: 
- Changes in DNA sequences
 - Plant reproduction
 - Natural disasters
 - Gamma radiation
 - biological diversity
 - DNA sequences staying the same
 - the environment
 - that material's properties


 

 Changes in DNA sequences        