In the case of peppered moth (Biston betutaria) the black-coloured form became dominant over the light-coloured form in England during industrial revolution. This is an example of

Step-by-step solution

The given case is an example of natural selection. As a result of struggle for existence only those organisms could survive, which have favourable variations to adapt environmental conditions on with so many variations in populations of species the struggle for existence results in survival of the fittest. The survival of the fittest is the result of selection and proliferation of only those organisms, which were most suitably adapted to the environment and most successful in mating, ie, natural selection.