How does earth's rotation cause day and night a as earth rotates toward east, the sun appears to rise in the west and set in the east b as earth rotates toward east, the sun appears to rise in the east and set in the west c earth rotates in a clockwise direction, whick makes the sun appear in the sky during the day d earth's rotation does not cause day and night , its revolution does

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.