Over time, data that support the successful
evolution of a species would include observations
that describe
(1) an increase in the genetic changes occurring
in body cells
(2) a decrease in the genetic variety carried in
sex cells
(3) an increase in the proportion of offspring
that have favorable characteristics
(4) a decrease in the proportion of the population
that has beneficial traits

The answer is (3) an increase in the proportion of offspring that have favorable characteristics.

In natural selection, genotype variations that will increase the chance of survival and reproduction of some organism are preserved and will be inherited. Peppered moth color variation is a good example of natural selection.During the Industrial revolution, due to pollution, trees become darker in the urban area. Light-colored moths were, thus, easy prey. The dark-colored moths were able to camouflage on dark trees and avoid predators. The phenomenon is known as industrial melanism. So, in polluted urban areas, the number of dark-colored peppered moths increased. In the clean environment, were much effective in hiding from predators and they outnumbered the dark-colored moths.
Therefore, the proportion of offspring that have favorable characteristics in such environment will increase.

The answer is constant.