All of the following are true about the life cycle of mosses EXCEPT: a. the growing embryo gives rise to the gametophyte b. external water is required for fertilization c. the gametophyte generation is dominant d. flagellated sperm are produced e. antheridia and aronia are produced by gametophytes

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.