What is a pollen grain?

You can tell from this karyotype that the individual is female because the karyotype has two chromosomes labeled

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 direct energy source that drives atp synthesis during respiratory oxidative phosphorylation is