Bunuel wrote:
Saguaro kangaroo rats generally leave watering holes, where food and water are abundant, during the day, while Sonoran kangaroo rats remain near these same watering holes and continue foraging throughout the day Although Sonoran kailgaroo rats have larger and more frequent litters, they are generally outnumbered by the Saguaro kangaroo rat.
Which of the following, if true, would best resolve the apparent paradox described above?
A. Several species of successful rodents also leave the streams and watering holes during the day
B. The Saguaro kangaroo rat matures much more slowly than the Sonoran kangaroo rat because of its relatively limited food supply.
C. Many of the predators of kangaroo rats, such as falcons and rattlesnakes, are only active around streams during the day.
D. Saguaro kangaroo rats are more sensitive to sunlight than are Sonoran kangaroo rats.
E. Sonoran kangaroo rats are reproductive to a greater age than are Saguaro kangaroo rats.
The answer is C.
The paradox is that Saguaro kangaroo rats are more numerous than Sonoran kangaroo rats, even though Sonoran kangaroo rats have larger and more frequent litters. The answer that best resolves this paradox is that Saguaro kangaroo rats are more likely to survive to reproductive age because they are less likely to be eaten by predators. This is because the predators of kangaroo rats, such as falcons and rattlesnakes, are only active around streams during the day, and Saguaro kangaroo rats leave the streams and watering holes during the day.
The other answers do not resolve the paradox. Answer A simply states that other species of rodents also leave the streams and watering holes during the day. This does not explain why Saguaro kangaroo rats are more numerous than Sonoran kangaroo rats. Answer B states that Saguaro kangaroo rats mature more slowly than Sonoran kangaroo rats. This does not explain why Saguaro kangaroo rats are more numerous, since it would be expected that Sonoran kangaroo rats would have more offspring over their lifetime. Answer D states that Saguaro kangaroo rats are more sensitive to sunlight than Sonoran kangaroo rats. This does not explain why Saguaro kangaroo rats are more numerous, since it would be expected that Sonoran kangaroo rats would be more likely to survive in the desert environment. Answer E states that Sonoran kangaroo rats are reproductive to a greater age than Saguaro kangaroo rats. This does not explain why Saguaro kangaroo rats are more numerous, since it would be expected that Sonoran kangaroo rats would have more offspring over their lifetime.