If you rub your finger across the body of an earthworm, you may notice little ripples. Earthworms were among the first organisms to display .

a coelom,

segmentation,

jointed appendages,

an endoskeleton

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.