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

Fact 2: Gene flow is the movement of alleles in or out of a population.

Given the two facts above, answer the question "What occurs when individuals move into a population?" with the following options: 
- resistance
 - spread flower seeds
 - rapid expansion
 - alleles move in
 - Leptospirosis
 - survival
 - competition
 - permineralization


 

    alleles move in     