The UCSD campus male junco population tails were, on average, 36 percent white, whereas the tails of males from nearby mountain populations averaged 40–45 percent white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to .

Which of these is the best example of a cause-and-effect chain of events? 1. alonzo went to the music festival. 2. carmen went to the same music festival. 3. alonzo met carmen at the music festival. 1. yosef bought a new car from a dealership. 2. bailey bought a car from the same dealership. 3. bailey paid more for his car than yosef did. 1. the high school football team played a game on friday night. 2. the drama club put on a play on friday night. 3. maya watched the football game instead of the play. 1. a fast food restaurant ran an advertisement on television. 2. hank saw the advertisement and got hungry. 3. hank went to the fast food restaurant and bought food.