Answer:
Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.
Explanation:
Evolution, in genetic terms, involves a change in the frequency of alleles in a population over time. What are the sources of genetic variation? Three sources of genetic variation are mutation, genetic recombination during sexual reproduction and lateral gene transfer.
The answer would be D, Schwann cells, because they are a part of the myelin sheath (which covers the neurons). c:
The fibrous skeleton of the heart
functions in all of the ways listed in the option, except causing direct spread
of electrical impulses from the atria to the ventricles. The fibrous skeleton
in fact supports proper coordination of atrial and ventricular contractions by
blocking direct spread of electrical impulses from atria to ventricles.
