A human skin cell contains 46 chromosomes. A frog sperm cell contains 12 chromosomes. Which
pair of numbers shows the chromosome number of
a normal gamete from each of these species?

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.

The most famous fossil called archaeopteryx is which of the following? a dinosaur a fern a fish a bird

When fossil fuels are burned, carbon dioxide is released. how does this gas impact the environment?