Match each planet to an accurate characteristics Mercury
Mars
Its diameter is less than
one-half the length of
Earth's diameter
Earth
Venusual
Its atmosphere contains
thick clouds of sulfuric
gas
Its atmosphere is mostly
nitrogen
It experiences large dust
storms.

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.