A species of fern can grow in a range of light conditions, and most individuals
in a population thrive in medium light. Suppose ferns that thrive in low light
become more common over time in the population.
Which two sentences must be true for this adaptation to occur through
natural selection?
A. The ferns became isolated from other fern populations and
developed new traits.
B. Spores from another fern population that thrives in low light were
blown into the area and grew into new ferns.
C. The ability to thrive under certain light conditions is an inheritable
trait.
D. Ferns that thrive in low light have an advantage in the population.