The industrial melanism phenomenon demonstrates __________

Industrial melanism is a classic example of natural selection in action.

Before the industrial revolution in England, light-colored peppered moths were well camouflaged against the light-colored lichens on tree trunks, while dark-colored (melanic) moths were easily spotted and preyed upon by birds. As industrial pollution increased, soot darkened the tree trunks and killed the lichens. This environmental change made the light-colored moths more visible to predators, whereas the dark-colored moths became better camouflaged.

Consequently, the dark-colored moths had a higher survival rate and reproduced more successfully, leading to an increase in their population frequency. This shift in the population's characteristics due to environmental pressures demonstrates natural selection.

Answer: natural selection