Fact 1: Gene flow occurs when individuals move into or out of a population.

Fact 2: Gene flow increases genetic variation within a population.

Given the two facts above, answer the question "what increases genetic variation?" with the following options: 
- selection
 - similiarity
 - colors of the spectrum
 - Plant reproduction
 - biological diversity
 - natural disasters
 - population movement
 - rapid expansion


 

       population movement  