Neo-Darwinism believes that new species develop from which of the following?

Assertion : Natural selection is the outcome of difference 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.

Which one of the following is correct with respect to Allopatric speciation?

The most likely reason for the development of resistance against pesticides in insects damaging a crop is

Due to specific mating behaviour,the members of a population do not mate in . . . . . . type of isolation.

The idea of "survival of the fittest" was given by