Which one of the following phenomena supports Darwin's concept of...

According to Darwin's theory of natural selection, The individual possessing useful variations survive whereas the others are eliminated. Nature selects the best suited and discards the others (survival of the fittest). Pesticide resistant insects are selected over pesticide sensitive insects by nature, and are thus survive through the course of evolution, until more suited (fittest) individual is selected, eliminating the former. Related Theory Darwinism can explain the survival of fittest but is unable to account for arrival of the fittest. It is difficult to suppose that small variations could have formed organs like wings and mimicry colouration which are useful only in their fully developed state but what about their presence in early stages.