Variations are beneficial for the survival of the species. Populations of organisms fill well-defined places, or niches, in the ecosystem, using their ability to reproduce.However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.
All of the above are correct.
Answer:
The hair is made up of 95% keratin, a fibrous, helicoidal protein (shaped like a helix) that forms part of the skin and all its appendages (body hair, nails, etc.). Keratin is synthesized by keratinocytes and is insoluble in water, thus ensuring impermeability and protection for the hair.
Explanation:
The answer is behavioral isolation.
Reproductional isolation is a way to prevent closely related species to mate each other. This is due to reproductive barriers which can be either prezygotic (before fertilization) and postzygotic (after fertilization) barrier. Behavioral isolation is an example of postzygotic barrier. It is based on behavior, including mating sounds and rituals. Thanks to behavior isolation, the different species (in this example gentoo penguins and emperor penguins) will have different mating rituals so they could attract only individuals of their own species, respectively.