If adecrease in differentiation tends to occur when individuals move in and out of a population, then what tends to occur when individuals move in and out of a population?

Answer choices:
- By wind and rain
 - permineralization
 - The bending of a ray of light
 - Something with a head, thorax, and abdomen
 - a decrease in differentiation
 - competing for resources
 - barks and snarls
 - metabolic reaction

 

     a decrease in differentiation     