After an oil spill, rehabilitation centers were set up to save sea otters by removing oil from them. The effort was not worthwhile, however, since 357 affected live otters and 900 that had died were counted, but only 222 affected otters, or 18 percent of those counted, were successfully rehabilitated and survived. Further, the percentage of all those affected that were successfully rehabilitated was much lower still, because only a fifth of the otters that died immediately were ever found.
Summarize Argument
The author concludes that the effort to save sea otters by removing oil from them wasn’t worthwhile. He supports this by saying that only 18% of counted otters were successfully rehabilitated and that this percentage is actually even lower because only a fifth of the otters that died immediately were ever found.
Notable Assumptions
The author assumes that a low success rate means that the rehabilitation effort wasn’t worthwhile, ignoring the possibility that a small number of rehabilitated otters might have significant positive ecological value or long-term benefits.
He also assumes that the reported number of otters is accurate, without addressing the possibility that the dead otters that were never found can’t be accurately counted. (?)
Note: We’re looking for the answer choice that “calls into question evidence offered in support of the conclusion.”
A
Do sea otters of species other than those represented among the otters counted exist in areas that were not affected by the oil spill?
The author’s argument only addresses rehabilitation efforts among the otter population that was affected by the oil spill. Surely other otter species exist in other places, but their existence doesn’t call into question the evidence offered in support of the author’s conclusion.
B
How is it possible to estimate, of the sea otters that died, how many were not found?
This calls into question the author’s evidence. He claims that the percentage of successfully rehabilitated otters is much lower than 18% because only a fifth of the dead otters were ever found. But how can he know that this number is accurate if the otters were never found?
C
Did the process of capturing sea otters unavoidably involve trapping and releasing some otters that were not affected by the spill?
Like (A), the author’s argument is only concerned with those otters that were affected by the spill. The effects of the rehabilitation process on other otters doesn’t call into question his evidence, which only addresses affected otters.
D
Were other species of wildlife besides sea otters negatively affected by the oil spill?
The author’s evidence only addresses sea otters that were affected by the oil spill. Whether other species of wildlife were also affected is irrelevant, since the rehabilitation efforts in question only involved sea otters.
E
What was the eventual cost, per otter rehabilitated, of the rehabilitation operation?
The author doesn’t mention cost as a factor in his assessment of whether the rehabilitation effort was worthwhile. (E) thus doesn’t call into question the author’s evidence, which only addresses the percentage of otters that were rehabilitated.
Summarize Argument
Adobe—a type of clay—is a great building material for desert environments because heat takes a long time to pass through it, meaning the clay heats up and cools down slowly. As a result, adobe houses stay warm during cool evenings and remain cool during hot days, keeping the temperature comfortable. In contrast, houses made of other materials allow heat to pass through quickly, so they become hot during the day and cold at night.
Identify Conclusion
Adobe the perfect material for building homes in the desert.
A
Adobe is a suitable substitute for other building materials where the heat-conduction properties of the structure are especially important.
This is a necessary assumption of the argument. The argument concludes that adobe is better for building houses in the desert than other materials. This implies that adobe can replace other materials in deserts where controlling heat is important.
B
In the desert, adobe buildings remain cool during the heat of the day but retain the warmth of the sun during the cool evenings.
This is a premise. The passage explains how adobe keeps houses cool during the day and warm at night to support the conclusion that adobe is a great material for building homes in the desert. Since this claim supports the argument, it can’t be the argument’s main conclusion.
C
Because adobe conducts heat very slowly, adobe houses maintain a pleasant, constant temperature.
This refers to two premises. The passage explains that adobe conducts heat slowly, which helps keep houses at a steady temperature. This fact supports the claim that adobe is an ideal building material for desert environments. As it supports the argument, it isn’t the conclusion.
D
Ideally, a material used for building houses in desert environments should enable those houses to maintain a pleasant, constant temperature.
This is a necessary assumption. The argument concludes adobe is ideal because it helps desert houses stay at a comfortable, steady temperature. This means the argument assumes that a good building material for desert houses should help keep the temperature pleasant and constant.
E
Adobe is an especially suitable material to use for building houses in desert environments.
This accurately states the main conclusion. The passage says that adobe is an “ideal” material for building in the desert, meaning it’s especially good for that purpose. It specifies that adobe is ideal for constructing desert homes because it regulates house temperature.
"Surprising" Phenomenon
Why did the second study report a smaller percent of plants as having patterned stems than did the earlier study, even though the two studies covered approximately the same geographical area?
Objective
The correct answer should help differentiate the second study from the first in a way that could lead to a smaller proportion of the plants being reported to have patterned stems.
A
The first study was carried out at the time of year when plants of the species are at their most populous.
How populous the plant was during the study doesn’t impact the proportion of those plants with patterned stems. In the 1st study, 70% were reported to have patterned stems, and in the 2nd, that % went down. The number of plants in each study doesn’t impact % with patterned stems.
B
The first study, but not the second study, also collected information about patterned stems in other plant species.
We’re trying to explain the decrease in % reported to have patterned stems in a particular species of plants. What happened with other plant species has no impact.
C
The second study included approximately 15 percent more individual plants than the first study did.
The comparative number of plants in the studies doesn’t impact the proportion of those plants with patterned stems. In the 1st study, 70% were reported to have patterned stems. In the 2nd, that % went down. The number of plants in each study doesn’t impact % with patterned stems.
D
The first study used a broader definition of “patterned.”
A broader definition of “patterned” in the first study means that in the first study, any given plant was more likely to be considered “patterned” than in the second study. This could explain why the % reported to have patterned stems decreased in the second study.
E
The focus of the second study was patterned stems, while the first study collected information about patterned stems only as a secondary goal.
Whether counting patterned stems was a primary or secondary goal doesn’t explain why the % reported to have patterned stems decreased in the second study. We have no reason to think the focus of the study would change the likelihood a given plant would be counted as patterned.
Summarize Argument
The author concludes that universities today offer a more in-depth and cosmopolitan education. She supports this by pointing out that, in the past, most university history courses only required textbooks that overlooked key parts of African, Asian, and American indigenous history and culture, but most university history courses today do not have these limitations.
Notable Assumptions
The author assumes that changes in history courses reflect overall changes in university education. She assumes that university education is more in-depth and global simply because history textbooks are now more in-depth and global. She assumes that other aspects of university education, like lectures or assignments, and subjects beyond history, are also more in-depth and cosmopolitan.
A
The history courses that university students find most interesting are comprehensive in their coverage of various periods and cultures.
Irrelevant. It doesn’t matter which course students find most interesting. Just because students find these courses most interesting doesn’t mean that they reflect university education overall.
B
Many students at universities whose history courses require the reading of books covering all periods and world cultures participate in innovative study-abroad programs.
Irrelevant. Universities whose history courses require books that cover all periods and cultures are likely not representative of “most universities today.” Regardless, we still don’t know whether culturally inclusive history courses reflect a cosmopolitan education.
C
The extent to which the textbooks of university history courses are culturally inclusive is a strong indication of the extent to which students at those universities get an in-depth and cosmopolitan education.
This suggests that history course material is representative of education overall. In other words, the fact that university history textbooks are more in-depth, cosmopolitan, and culturally inclusive does indicate that university education is also more in-depth and cosmopolitan.
D
Universities at which the history courses are quite culturally inclusive do not always have courses in other subject areas that show the same inclusiveness.
This weakens the argument by suggesting that university history courses are not representative of university education as a whole. If other subjects aren’t more culturally inclusive, the author can’t conclude that university education overall is more in-depth and cosmopolitan.
E
University students who in their history courses are required only to read textbooks covering the history of a single culture will not get an in-depth and cosmopolitan education from these courses alone.
Irrelevant. (E) doesn’t suggest that students who read textbooks that cover the history of many cultures will get an in-depth and cosmopolitan education. We still need to know whether history course material is representative of overall education.
Summarize Argument: Counter-Position
The author concludes that the government’s proposal to publish reports of airline statistics will actually make the public less informed about airline safety because the reports will likely be incomplete.
Identify and Describe Flaw
This argument is flawed because it fails to consider the fact that reports can still inform the public about airline safety even if they’re incomplete. While it’s fair to assume that an incomplete report would be less informative than a complete one, an incomplete report is still better than nothing. Even if the reports are missing some information, there’s no reason to believe that they’d make the public less informed than if this kind of information weren’t made public at all.
A
fails to consider that, even if the reports are incomplete, they may nevertheless provide the public with important information about airline safety
This describes how the argument fails to consider that a report can still help inform the public even if it’s missing some information.
B
presumes, without providing justification, that the public has a right to all information about matters of public safety
The argument never assumes anything about people’s rights. It only claims that this policy will undermine the goal of informing the public.
C
presumes, without providing justification, that information about airline safety is impossible to find in the absence of government disclosures
The argument doesn’t assume that government disclosures are necessary to finding this information. In fact, the author claims that the government’s actions are counterproductive in this case.
D
presumes, without providing justification, that airlines, rather than the government, should be held responsible for accurate reporting of safety information
The argument makes no claim about who should be responsible for reporting this information. It only claims that this policy is counterproductive to the goal of informing the public.
E
fails to consider whether the publication of airline safety statistics will have an effect on the revenues of airlines
This is irrelevant. The argument is only concerned with whether or not this policy is effective at informing the public. It doesn’t matter what effect it has on airlines’ revenues.
Summarize Argument
The author concludes that financial rewards don’t provide the strongest incentive when people are choosing one job over another. This is based on surveys showing that most people don’t name high salary as the most desirable feature of a job.
Notable Assumptions
The author assumes that the reason most people don’t name high salary as the most desirable feature of a job is because financial rewards aren’t the strongest incentive for them. But this overlooks the possibility that a high salary is just one component of “financial rewards.” Other financial rewards could provide the strongest incentive when choosing a job, even if salary doesn’t provide the strongest incentive.
A
Even high wages do not enable people to obtain all the goods they desire.
The author never assumed that high wages allow people to obtain every good they want. Even if they don’t, the survey results can still indicate that financial rewards aren’t the strongest incentive when choosing jobs.
B
In many surveys, people say that they would prefer a high-wage job to an otherwise identical job with lower wages.
This establishes that for the exact same job, people prefer higher wages. But the author never assumed people don’t care about money at all. The author’s position is that money isn’t the strongest incentive. But it can still be an incentive.
C
Jobs that pay the same salary often vary considerably in their other financial benefits.
This points out that “financial rewards” can include other aspects besides a high salary. For example, stock options or bonuses. This shows why the survey results, concerning only salary, don’t show that financial rewards are not the strongest incentive for people choosing jobs.
D
Many people enjoy the challenge of a difficult job, as long as they feel that their efforts are appreciated.
This points to something else people value about a job. If it does anything, it goes in the direction of supporting the author’s position that there are other parts of a job that could be a stronger incentive for choosing one job over another.
E
Some people are not aware that jobs with high salaries typically leave very little time for recreation.
This suggests that for some people, they don’t know ahead of time the downsides of jobs with high salaries. This doesn’t point out why the survey results don’t support the author’s conclusion.