Industrial melanism is an observation which supports evolution by:

natural selection

The correct answer is Option (3) → natural selection

Industrial melanism was primarily highlighted in moths, specifically the peppered moth (Biston betularia). This phenomenon refers to the evolutionary change observed in the coloration of peppered moths during the industrial revolution in Britain. As pollution increased and trees became darker due to soot, the population of darker, melanistic forms of the peppered moth increased in industrial areas, demonstrating natural selection favoring moths that were better camouflaged against darkened tree trunks. This adaptation is a classic example of natural selection and is often cited in evolutionary biology to illustrate the impact of environmental changes on species' adaptations.

Before industrialization set in, it was observed that there were more white-winged moths on trees than dark-winged but after industrialization, i.e., in 1920, there were more dark-winged moths in the same area, i.e., the proportion was reversed. During the post-industrialization period, the tree trunks became dark due to industrial smoke. Under this condition the white-winged moth did not survive due to predators, dark-winged or melanised moth survived.