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?
1) The ferns became isolated from other populations.
2) The ferns developed a resistance to high light conditions.
3) The ferns reproduced more successfully in low light conditions.
4) The ferns migrated to a different habitat.