How might environmental manipulation of a crop have unexpected consequences? a. The new crop may require more water than the original. b. The crop may harm the environment. c. The yield may be reduced. d. All of the above Please select the best answer from the choices provided A B C D

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.