Summary
Hot spots are places with the highest concentrations of endemic species. Habitats at many hot spots are threatened by commercial development. This threatens the endemic species in these hot spots. Most extinctions involve loss of endemic species.
Strongly Supported Conclusions
We’re looking to fill in a blank concerning what would be reasonable to do for organizations dedicated to preserving species, given that these organization can’t fight for every environmental cause. The evidence suggests it’s reasonable for these organizations to try to protect hot spots from commercial development.
A
try to help only those species who are threatened with extinction because of habitat loss
Unsupported. The stimulus gives us evidence about hot spots and the threats to species in hot spots. This conclusion isn’t focused on hot spots. Species threatened because of habitat loss includes more than just species threatened in a hot spot. So this conclusion is too broad.
B
concentrate their resources on protecting hot spot habitats
Strongly supported. The evidence concerned endemic species in hot spots, and a significant proportion of extinctions involve endemic species. So there’s strong reason to focus on protecting hot spots, which are defined as the places with the most endemic species.
C
treat all endemic species as equally valuable and equally in need of preservation
Unsupported. The stimulus may support that idea that endemic species are more in need of protection than non-endemic species. But we don’t have enough to draw conclusions about individual endemic species compared to other endemic species. Some may be more important than others.
D
accept that most endemic species will become extinct
Unsupported. The stimulus doesn’t support giving up. It supports directing efforts to hot spots. We don’t have any basis to say these effort are likely to fail or that organizations should just accept species loss. Maybe there efforts can succeed and save most endemic species.
E
expand the definition of “hot spot” to include vulnerable habitats that are not currently home to many endangered species
Unsupported. The stimulus supports a conclusion about where organizations should focus their efforts concerning species protection. Expanding the definition of hot spot wouldn’t help protect more species, because we don’t know if anyone is trying to protect hot spots yet.
Application: Wilton sold a used bicycle to Harris, knowing very little about its condition. Wilton told Harris that the bicycle was in good working condition, but Harris soon learned that the brakes were defective. Wilton was therefore guilty of fraud.
Summarize Argument
The author concludes that Wilton was guilty of fraud. This is based on the following:
If one sells an item that they know is defective, but tells the buyer that the item is not defective, that constitutes fraud.
Wilton sold a bicycle to Harris, without knowing whether it was defective.
Wilton told Harris the bicycle was not defective, but it turned out to be defective.
Identify and Describe Flaw
The author assumes that Wilton knew the bicycle was defective. But all we know is that Wilton didn’t know about the bicycle’s condition. He might not have known that it was defetive.
A
the application fails to establish whether Wilton was given the opportunity to repair the brakes
Whether one has the opportunity to fix an item has nothing to do with the principle.
B
the application fails to indicate how much money Wilton received for the bicycle
The amount of money received for an item has nothing to do with the principle.
C
the application uses the word “defective” in a sense that is crucially different from how it is used in the statement of the principle
The word “defective” is not used in two different ways.
D
Harris might not have believed Wilton’s statement about the bicycle’s condition
Whether the buyer believes what the seller says has nothing to do with the principle.
E
asserting something without justification is not the same as asserting something one knows to be false
Wilton asserted that the bicycle was not defective, even though he didn’t have justification for that claim. But this is not the same as saying that an item is not defective while knowing that it is. Wilton did not know it was defective.
Summary
Engine noise from boats traveling through killer whales’ habitats ranges from a frequency that overlaps with the acoustical range in which the whales communicate with each other. Although the whales do not act differently when the engine noise is present, the noise can be loud enough to cause hearing damage over time. Therefore… (the correct answer will be the conclusion).
Strongly Supported Conclusions
The engine noise could impact how killer whales communicate with each other after enough time.
A
younger killer whales are better able to tolerate engine noise from boats than older whales are
This is not supported by the stimulus and requires some unreasonable assumptions to make it work. You must assume that younger killer whales have been exposed to engine noise for a shorter period of time than older ones.
B
killer whales are less likely to attempt to communicate with one another when boat engines are operating nearby
The stimulus does say anything about what killer whales prefer.
C
noise from boat engines may impair killer whales’ ability to communicate
The stimulus says that engine noise *can* damage hearing loss over time. Killer whales communicate through screams and squeals. So, it is easy to support that boat engines could eventually impair the whales’ ability to communicate.
D
killer whales are most likely to prefer areas where boat traffic is present, but light
There is no support anywhere in the stimulus about what killer whales “prefer.”
E
killer whales would probably be more successful in finding food if boats did not travel through their habitats
You have to assume that killer whales communicate to find food. There is no evidence in the stimulus that supports this assumption.
Summarize Argument
The author concludes that Bruch Industries isn’t a member of the trade group. This is based on the fact that every company listed in a particular document belongs to the trade group, and Bruch Industries isn’t listed in that document.
Identify and Describe Flaw
The author confuses a sufficient condition for being in the trade group with a necessary condition. Being on the list is sufficient to know that a company is in the trade group, because every company listed is a member of the trade group. But that doesn’t mean being on the list is required to be a member. It’s possible for a company to be a member even if it’s not on the list. In other words, “Every company on the list is in the group” does not imply “every company in the group is on the list.”
A
gives no reason to think that Bruch Industries would want to belong to the trade group
Bruch’s desires are irrelevant to the argument. The argument concerns whether the company is a member of the trade group, not whether it wants to be.
B
does not present any evidence that the document names every member of the trade group
The author fails to show that the document lists all of the members of the group. That’s why not being listed in the document doesn’t imply lack of membership in the group.
C
does not explain how it is that the trade group could have inadvertently sent out a secret document
It doesn’t matter how the author got the secret document. We know the document exists and the trade group confirmed that everyone on the list is a member of the group.
D
presents no reason why Bruch Industries would not want its membership in the trade group to be known
Brush’s desires are irrelevant to the argument. The argument concerns whether Brush is a member of the group, not whether it would want its membership to be known.
E
takes for granted the accuracy of a statement by a representative who had a reason to withhold information
The representative confirmed that every company listed in the document is a member of the group. The reasoning isn’t flawed because the author accepts the representative’s confirmation. We have no reason to think this confirmation is inaccurate.
Yoko: Children’s stories still tend to have clearly immoral characters in them, but now these characters tend not to be the sort that frighten children. Surely that’s an improvement.
Speaker 1 Summary
Peter argues that children’s stories should include clearly immoral characters (which they usually did in the past, but now do not). Why? Because it’s important to teach children the consequences of being bad.
Speaker 2 Summary
Yoko doesn’t make an argument, but does make several factual claims. First, modern children’s stories usually do have clearly immoral characters. Second, these characters are less frightening than in the past. And finally, it’s a good thing to avoid frightening children.
Objective
We’re looking for a disagreement between Peter and Yoko. The two disagree about whether modern children’s stories usually contain clearly immoral characters.
A
should be less frightening than they are
Neither speaker makes this claim. Yoko is the only one to talk about stories being frightening, but never says that stories should be less frightening than they currently are.
B
tend to be less frightening than earlier children’s stories were
Yoko agrees with this, but Peter doesn’t express an opinion. Peter doesn’t talk about children’s stories being frightening at all, either now or in the past.
C
differ significantly in overall quality from earlier children’s stories
Neither speaker talks about the overall quality of children’s stories, currently or in earlier times, let alone to compare the two.
D
tend to have clearly immoral characters in them
Peter disagrees with this but Yoko agrees, so this is the speakers’ disagreement. Peter states that modern stories, unlike earlier ones, don’t usually have clearly immoral characters. Yoko, however, says that modern stories usually do have clearly immoral characters.
E
should help children learn the consequences of being bad
Peter agrees with this, but Yoko doesn’t express an opinion. Yoko never discusses what kinds of lessons children’s stories should impart on their readers.
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that an overabundance of algae is harmful to smaller fish in this pond. This is based on the fact that over the past 15 years, the few times that the author has seen a lot of dead small fish has coincided with the times that he has noticed unusually large amounts of algae in the water.
Identify and Describe Flaw
The author assumes that the correlation between lots of dead small fish and lots of algae is explained by algae causing harm to the small fish. This overlooks alternate explanations for the correlation. Perhaps there’s a third factor that causes both the algae and the dead fish. The author also assumes that his own observations of the timing of dead small fish and lots of algae is representative of the general pattern of dead small fish and lots of algae in the pond.
A
presumes, without providing justification, that smaller fish are somehow more susceptible to harm as a result of overabundant algae than are larger fish
The author never compares the effects of algae to the effects of larger fish.
B
fails to consider that the effects on smaller fish of overabundant algae may be less severe in larger bodies of water with more diverse ecosystems
The author’s conclusion doesn’t concern other bodies of water besides “this pond.”
C
ignores the possibility that the same cause might have different effects on fish of different sizes
The author’s conclusion only concerns the effects of algae on “smaller fish.” Fish of other sizes are not relevant to the argument.
D
ignores the possibility that the overabundance of algae and the deaths of smaller fish are independent effects of a common cause
This possibility presents an alternate explanation for the author’s evidence. Perhaps algae isn’t harmful to smaller fish, but rather the algae and deads of small fish are both results of some other cause.
E
ignores the possibility that below-normal amounts of algae are detrimental to the pond’s smaller fish
The author didn’t say that below-normal amounts of algae are not harmful to smaller fish. The conclusion is that overabundance of algae is harmful, but this doesn’t imply that the author thinks less than abundant algae isn’t harmful.
Saldana: Political debates almost always benefit the candidate who has the better debating skills. Thus, they don’t really help voters determine which candidate is most qualified for office.
Speaker 1 Summary
The public should demand political debates before elections. Why? Because by watching a debate, voters are better able to choose which candidate is best suited for office.
Speaker 2 Summary
Political debates don’t help voters determine which candidate is best suited for office. Why? Because debates benefit the candidate who has the better debating skills.
Objective
We need a statement that Tanner and Saldana disagree on. Tanner thinks that debates help voters determine which candidate is best suited for office. Saldana thinks that debates don’t really help voters make this determination.
A
Political candidates with strong debating skills are more likely to win elections than those with weak debating skills.
Tanner does not express an opinion on this statement. We only know that Tanner believes political debates help voters make their decisions.
B
A voter who watches a political debate will likely be better able, as a result, to determine which candidate is more qualified for office.
Tanner and Saldana disagree on this statement. Tanner agrees and that’s why he thinks there should be political debates before every election. Saldana disagrees because she thinks debates only reflect a candidate’s debating skills, not whether they are best suited for office.
C
Debating skills are of little use to politicians in doing their jobs once they are elected to office.
Tanner does not express an opinion on this statement. Tanner may think that debating skills help voters determine a candidate’s suitability, but he does not express whether these skills are useful or not after candidates are elected.
D
The candidates with the best debating skills are the ones who are most qualified for the political offices for which they are running.
Tanner does not express an opinion on this statement. We only know that Tanner thinks that debates are informative for voters. We don’t know whether Tanner thinks the debating skills specifically are indicative of a candidate’s suitability.
E
Political debates tend to have a major effect on which candidate among those participating in a debate will win the election.
Tanner does not express an opinion on this statement. We don’t know whether Tanner thinks that debates causally effect a candidate’s chances of winning an election.
"Surprising" Phenomenon
Why do the busiest highways have the fewest fatal accidents?
Objective
Any hypothesis explaining this phenomenon must rely on a difference between the highways carrying the most traffic and other highways. This difference must explain why fatal accidents are less likely on the busiest highways than on other types of highways.
A
Drivers have more accidents when they become distracted.
It is not implied whether drivers on the busiest highways are more or less likely to become distracted than drivers on other highways, so this is useless without more information.
B
The highways that have the highest rate of fatal accidents have moderate volumes of traffic.
This adds more detail to the phenomenon without explaining it. It does not address the busiest highways, or explain why they have fewer fatal accidents than other types of highways.
C
Most of the motorists on very heavily traveled highways tend to be commuting to or from work.
It is not implied whether commuters are more or less likely than other drivers to be in a fatal accident, so this is useless without more information.
D
Most serious accidents occur when vehicles are moving at a high rate of speed.
This explains why the busiest highways have the lowest rate of fatal traffic accidents. Because of their congestion, these highways are less likely to carry fast-moving vehicles, and so are less likely to be the site of fatal accidents.
E
Heavily traveled highways do not always carry a higher proportion of large trucks.
This does not imply that the busiest highways carry fewer trucks than other highways. It allows for the possibility that they often or usually carry a higher proportion of large trucks than other highways.