Which of the following real-world examples models linear motion? a. throwing a rock in the air at a 60-degree angle b. throwing a rock in the air at a 45-degree angle c. running 50 m along a straight track d. running around the curve of a track

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.