Adaptation is one of the basic phenomena of biology.[1] It is the process whereby an organism becomes better suited to its habitat.[2] Also, the term adaptation may refer to a characteristic which is especially important for an organism's survival. For example, the adaptation of horses' teeth to the grinding of grass, or their ability to run fast and escape predators. Such adaptations are produced in a variable population by the better suited forms reproducing more successfully, that is, by natural selection.