Assertion : Natural selection is the outcome of differences in survival and reproduction among individuals that show variation in one or more traits. Reason : Adaptive forms of a given trait tend to become more common; less adaptive ones become less common or disappear.

Step-by-step solution

The Darwin Wallace theory of Natural Selection can be generalised as the changes in species by the survival of an organism exhibiting a natural variation that gives it an adaptive advantage in an environment. Thus leading to a new environmental equilibrium. The idea of the survival of the fittest explains the above evolution by natural selection. According to survival of fittest, some of the variations exhibited by living things make it easier for them to survive and reproduce thus more adaptive forms increase. Tho