Jane is a 23 y/o woman 57212# and has fairly good general health. Her resting heart rate is 70 bpm. She usually skips breakfast: has fast food such as Taco Bell or hamburgers and fries with a diet Coke for lunch and frozen dinners in the evening, often Chinese food BBQ or a pasta dish. She is lactose intolerant so she doesn't drink milk or eat cheeseShe's mainly sedentaryworking in an office and tied to her desk most of the day.

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.