What kind of weather would an anticyclone likely bring

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.

Oak and maple trees, chipmunks, white-tail deer, and black bears emerging from hibernation are all organisms that may be found in which biome

What happens when a scientific theory is shown to be an accurate description of a phenomenon?