Prep2012-Pack1-CR-039 VCR003744 Medium
Reasoning
What would the information about moths most help explain? We are told that larger moths can fly faster than small ones, can evade predators better, and have higher optimal body temperatures. We are also told that moths cannot fly or evade predators when air temperatures are much below their optimal body temperatures. Thus, in cooler temperatures, larger moths lose their advantages over smaller ones. And at temperatures too cool for large moths but not too cool for small moths, small moths can still evade predators while large moths cannot. Consider the answer choices and find one presenting an observation that these facts could explain.
A. This could help explain why large moths can evade predators better, but we are looking for an answer choice that the presented information can ex plain, not one that can explain the presented information.
B. Correct. For the reasons discussed above, the information suggests that large moths have a greater survival advantage in warmer climates and might be at a disadvantage in cooler ones.
C. Since the information suggests that larger moths must spend more time inactive on vegetation, if anything it implies that larger moths should have evolved more effective camouflage than smaller moths, not vice versa.
D. This could explain why large moths can fly faster, but we are for an answer choice that the presented information can explain, not one that can explain the presented information.
E. The differences between larger and smaller moths might make it harder for predators to prey on several different species of moths and are irrelevant to whether those predators also prey on other insects.
The correct answer is B.
Prep2012-Pack1-CR-040 VCR003839 Medium
Reasoning
What would make predation by killer whales more likely than disease to have reduced the sea otter population? The argument is that disease is a likely explanation for the declining sea otter population because disease also reduced seal and sea lion populations at the same time, whereas predation by killer whales is an explanation because the killer whale population did not change. The argument assumes that since the killer whale population did not increase, predation of sea otters by killer whales did not increase either. This reasoning would be weakened if the declining seal and sea lion populations led killer whales to eat more sea otters.
A. Correct. If the scarcity of seals and sea lions led killer whales to seek out other prey, the killer whales might have started eating more sea otters, thereby reducing the sea otter population.
B. This rules out a third possible explanation of the declining sea otter population, but disease could still be a more likely explanation than predation by killer whales.
C. The declining sea otter population could account for this observation regardless of what made the population decline.
D. The declining sea otter population could account for the increasing sea urchin population regardless of what made the sea otter population decline.
E. Even if seals and sea lions inhabit a wider area than sea otters do, a pollution-related disease affecting seals and sea lions could also affect sea otters.
The correct answer is A.
