During a trip to the galapagos islands, which observation led charles darwin to suspect that organisms change over time?
island finches were able to breed with mainland species.
island finches resembled mainland finches, but were not the same species.
island finches resembled extinct species from other islands around the world.
island finches did not have beaks of the same size and shape.
the anwser is b.

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.