Yaniyah is a cross country runner. She runs up a lot of hills. Some hills are very steep and some are much flatter. The steepness of the hills is an example of what?

Select the correct answer from each drop-down menu. in an experiment, dr. travis examined the effects of calcium intake on osteoporosis, a condition that causes an increased risk of bone fractures. the amount of calcium is variable. the risk of bone fractures .

Which is not a type of symmetry? a. asymmetryb. radial symmetryc. bilateral symmetryd. lateral symmetry

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.