The image above shows the changes in a moth population's coloring over time. which type of natural selection has occured and why?

question 3 options:

disruptive selection has occured because over time the extremes were favored.

directional selection has occured because over time the population shifted to one of the extremes.

stabilizing selection has occured because over time the extremes were favored against.

Based on the image above, the type of natural selection that has occurred is STABILIZING SELECTION. 

Stabilizing selection has occurred because over time the extremes were favored against.

Disruptive selection would result to having the population after selection curve move from one side of the original population curve. 
Diversifying selection would result to having the population after selection curve form a wave that is not in line with the original population curve.