Cichlids mostly inhabit shallow coastal waters in Lake Malawi and they have evolved mouth structures depending on whether they live in rocky outcrops, sandy areas, or heavily vegetated areas of the lake shore. The large number of fish species present in the East African Rift Lakes is an example of what type of evolutionary process? ​

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.