Natural selection refers to the choice made by nature for the survival of the fittest, for example beeteles, there were betteles of many colours like red n blue but they were prone to become the prey of crows n other animals. Due to this they slowly n gradually changed their colour from red to green so that they can camouflage easily in the green leaves. Those which were unable to evolve bacame extinct. This is natural selection, means nature itself bounds the species to evolve otherwise they are unable to survive.
