The result of attempting to whip cream in a blender is a thick, velvety substance rather than fluffy whipped cream. This is because a blender’s container does not let in enough air to whip cream effectively. Although using a special whipping-cream attachment in a blender can help somewhat, it cannot fully compensate for the container’s poor air intake.

Summary

Whipping cream in a blender results in a thick, velvety substance rather than fluffy whipped cream. This is because a blender’s container does not let in enough air to whip cream effectively. Using a special whipping-cream attachment in a blender can help somewhat, but it cannot fully compensate for the container’s poor air intake.

Notable Valid Inferences

Using a whipping-cream attachment in a blender is not sufficient to whip cream effectively.

A
Cream that has been whipped ineffectively generally becomes a thick, velvety substance rather than fluffy whipped cream.

Could be false. It is possible that cream that has been whipped ineffectively can become a substance that is not thick and velvety. We only know that cream specifically whipped in a blender becomes thick and velvety.

B
The use of a special whipping-cream attachment in a blender does not suffice to whip cream completely effectively.

Must be true. The stimulus tells that although this special attachment can help, the attachment cannot fully compensate for the container’s lack of air intake. Therefore, the special attachment is not sufficient to whip cream completely effectively.

C
When attempting to whip cream in a blender, using a special whipping-cream attachment always produces a fluffier result than could be obtained without using such an attachment.

Could be false. To claim that the attachment always produces a fluffier result is too extreme. The stimulus only tells us that the attachment can help somewhat.

D
The use of a special whipping-cream attachment in a blender can reduce the total amount of air required to whip cream effectively in that blender.

Could be false. We don’t have any information in the stimulus that suggests how the attachment functions. We only know that the attachment cannot fully compensate for the container, but we do not know in what ways the attachment actually compensates.

E
The use of a blender, with or without any special attachments, is not the most common way to attempt to produce whipped cream.

Could be false. To claim this is not the most common way is too extreme. It is possible that using a blender is the most common way, it’s just an ineffective way according to the stimulus.


25 comments

Astronomer: Proponents of the hypothesis that life evolved extraterrestrially and drifted here in spores point out that, 3.8 billion years ago, Earth was bombarded by meteorites that would have destroyed any life already here. Yet 3.5 billion years ago, Earth had life forms complex enough to leave fossil remains. Such life could not have evolved here in the 0.3 billion years following the meteorite bombardments, they claim. There is good reason to regard their hypothesis as false, however, for they merely offer empirical arguments against the view that life evolved on Earth; neither they nor anyone else has provided positive support for the extraterrestrial-spore theory of the origin of terrestrial life.

Summarize Argument: Counter-Position
The author concludes that there is good reason to regard as false the view that life evolved outside of Earth and drifted to Earth on spores. This is based on the fact that proponents of this view have not offered positive support for their view. Rather, they offer only arguments against the view that life evolved on Earth.

Identify and Describe Flaw
The author assumes that the proponents’ failure to provide evidence for their theory constitutes a reason to think their view is false. This overlooks the fact that their view can be true, despite the proponents’ failure to offer evidence for it.

A
concludes, simply because there is no evidence in favor of a hypothesis, that there is evidence against that hypothesis
The author thinks the fact proponents haven’t offered evidence in favor of their view constitutes a reason to think their view is false.
B
fails to justify its claim that the view being criticized is inherently implausible
The author doesn’t claim that the proponents’ view is “inherently” implausible. The author’s reasoning is based on the fact proponents haven’t offered evidence for it.
C
reasons that a hypothesis is false simply because there is another hypothesis that is equally likely to be true
The author doesn’t point out another hypothesis that is “equally likely” to be true.
D
attempts to derive a conclusion from premises that contradict it
The author’s premises do not contradict the conclusion. The premises establish that the proponents haven’t offered evidence for their view. This doesn’t contradict the claim that the proponents’ view is false.
E
grants the truth of claims that are made by the advocates of the hypothesis but that do nothing to strengthen the astronomer’s own argument
The author doesn’t accept the claims of the proponents as true. He simply describes those claims in the first half of the stimulus. But the author then rejects the proponents’ hypothesis because they haven’t offered positive evidence for it.

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Activist: Accidents at the Three Mile Island and Chernobyl nuclear plants have shown the dangers of nuclear power. It was earlier argued that nuclear power was necessary because fossil fuels will eventually run out. Recently, however, a technology has been developed for deriving from sewage sludge an oil that can be used to generate power. This new technology, therefore, together with the possibility of using alternative sources of energy like solar, wind, and hydroelectric power, raises the hope that we can dispense altogether with nuclear power and that we can meet our energy needs in a way that better protects the environment from harm than we do at present.

Summarize Argument
The author concludes that a new technology that derives an oil from sewage sludge makes it possible that we can turn away from nuclear power and move towards environment-friendly energy. His support is that this sewage-sludge oil can be used to generate power

Notable Assumptions
The author assumes that the oil derived from sewage sludge, along with the myriad alternatives listed, would in fact be able to replace nuclear power. He also assumes that doing so would in fact result in less environmental damage than nuclear power does, which means he believes the process of extracting and storing oil from sewage sludge isn’t as environmentally taxing as nuclear power. Finally, the author assumes that relying on sewage sludge isn’t as much of a danger as nuclear power.

A
whether the current methods of disposing of sewage sludge by dumping do environmental damage
If the current method of disposing of sewage sludge is environmentally harmful, then a process relying on sewage sludge would be environmentally harmful. This would weaken the author’s argument that sewage-sludge oil will be environmentally beneficial versus nuclear power.
B
whether the processes that are used to turn sewage into clean water and sewage sludge have been improved in recent decades
Irrelevant. We don’t care if sewage sludge and water are being properly separated. We’re interested in whether an oil extracted from sewage sludge can in fact help replace nuclear power.
C
whether the cost of producing and using oil from sewage sludge would be economically sustainable
If producing and using an oil from sewage sludge isn’t economically sustainable, then that oil certainly won’t replace nuclear power. If it is economically sustainable, then the author’s argument in favor of that oil is strengthened.
D
whether the burning of oil from sewage sludge would, in contrast to nuclear power production, produce gases that would have a harmful warming effect on climate worldwide
If burning that oil did produce harmful gases—an effect that nuclear power production doesn’t have—then the author’s claim that the sewage-sludge oil offers an environmentally-friendly alternative to nuclear power is seriously undermined.
E
whether waste products that would be produced in deriving oil from sewage sludge and burning it would be as dangerous as those produced by the mining and use of nuclear fuel
If such products were produced, then sewage-sludge oil would seem to have one of the same problems the author cites about nuclear power: danger to humans.

35 comments

In a study of tropical forests it was found that while the species of trees that is most common in a particular forest also reproduces the most, trees of the species that is rarest there tend to survive longer. This pattern holds regardless of which species of trees is the most common and which is the rarest.

"Surprising" Phenomenon
Why do trees of the rarest species in tropical forests survive longer than trees of the most common species, which reproduce the most?

Objective
The correct answer will be a hypothesis that explains a key difference between the rarest and most common species of trees in tropical forests. That difference must result in the trees of the rarest species surviving longer, either because of some quality or adaptation that is present among rare tree species, or because of overpopulation among common tree species.

A
The species of trees that is most common in a forest thrives there because it is best suited to the local climate.
This may help to explain why the common trees reproduce the most, but it doesn’t help to explain why the rarest trees survive longer. If the common trees are “best suited to the local climate,” shouldn’t they survive longer than the rarest trees?
B
Older trees tend to reproduce the least.
This doesn’t give us a key difference between the common species and the rarest species. Instead it gives us a similarity: that older trees of any species reproduce the least. We still don’t know why the rarest trees live longer while the common trees reproduce the most.
C
The study tracked preexisting tree species but did not introduce any new species to the tropical forests.
The fact that no new species were introduced doesn’t affect the study’s findings: the most common species reproduces the most, while the rarest species lives longer. We still need a key difference between rare and common species to explain these results.
D
The survival of the trees of the rarer species enables tropical forests to recover more easily from moderate destruction.
The positive effect of the rare trees doesn’t explain why they live longer. Presumably, the common trees also have positive effects on the forest. But we still don’t know why trees of the rarest species live longer than those of the most common species.
E
The trees of the common species have more competition for the resources they need than do the trees of the rare species.
This highlights a key difference between rare and common species that helps explain the study’s results. Common species face more competition for resources, which limits their lifespan, while trees of rare species, with less competition, tend to survive longer.

15 comments

The television star Markus Hermann refuses to grant interviews with newspapers unless he is given the right to approve the article before publication. The Greyburg Messenger newspaper refuses to do anything that its editors believe will compromise their editorial integrity. So the Messenger will not interview Hermann, since _______.

Summary

The author concludes that the Messenger will not interview Hermann. This is based on the fact that the Messenger won’t do anything that its editors believe will compromise their editorial integrity. In addition, in order to interview Hermann, he must be given the right to approve the article before publication.

Missing Connection

We know that if the editors think something will compromise their editorial integrity, the Messenger won’t do it. So to conclude that the Messenger won’t interview Hermann, we want to know that the editors think interviewing Hermann will compromise their editorial integrity, or that they think that what Hermann requires in order to conduct the interview (the right to approve the article before publication) will compromise their editorial integrity.

A
the editors of the Messenger believe that giving an interviewee the right to approve an article before publication would compromise their editorial integrity

(A), in connection with one of the premises, establishes that the Messenger will not grant Hermann the right to approve the article. Then, since Hermann won’t grant an interview unless he is given the right, (A) establishes that Hermann won’t grant the interview.

B
the Messenger has never before given an interviewee the right to approve an article before publication

(B) doesn’t establish that the Messenger won’t grant Hermann the right to pre-publication approval. Just because it’s never happened before doesn’t guarantee that it won’t happen this time.

C
most television stars are willing to grant interviews with the Messenger even if they are not given the right to approve the articles before publication

We know Hermann won’t grant an interview without pre-publication approval rights. What other TV stars do doesn’t matter.

D
Hermann usually requests substantial changes to interview articles before approving them

What Hermann actually does with pre-publication approval rights doesn’t matter. The issue is whether granting him the pre-publication approval rights is something that editors think compromises their editorial integrity.

E
Hermann believes that the Messenger frequently edits interviews in ways that result in unflattering portrayals of the interviewees

What Hermann beleives about Messenger edits doesn’t matter. The issue is whether granting him the pre-publication approval rights is something that editors think compromises their editorial integrity.


5 comments

Columnist: An information design expert has argued that using the popular presentation-graphics software GIAPS, with its autopresentation wizard and simplistic premade templates, leads people to develop ineffective presentations. But that is absurd. GIAPS is just a tool, so it cannot be responsible for bad presentations. The responsibility must lie with those who use the tool poorly.

Summarize Argument: Counter-Position
The author concludes that the responsibility for bad presentations that use GIAPS lies with the users, not with GIAPS. This is based on the fact that GIAPS is just a software tool. The author believes this supports the subsidiary conclusion that GIAPS can’t be responsible for bad presentations.

Identify and Describe Flaw
The author assumes that a tool can’t be responsible for bad presentations. This overlooks the possibility that a tool might lead people into making bad presentations. A tool can be hard to use or poorly designed, causing users to use it ineffectively.

A
bases its conclusion on claims that are inconsistent with each other
The claim that GIAPS is a tool does not contradict the claim that GIAPS can’t be responsible for bad presentations. The supporting claims are not inconsistent with each other.
B
takes for granted that any presentation that is not ineffective is a good presentation
The author arguably assumes that presentations that are ineffective are bad. But this doesn’t imply that the author believes presentations that are not ineffective are good. The author doesn’t make any assumptions about what constitutes good presentations.
C
bases an endorsement of a product entirely on that product’s popularity
The author’s conclusion is not an “endorsement” of a product. The author doesn’t say that GIAPS is good or that people should buy GIAPS. The conclusion is only that GIAPS is not responsible for bad presentations.
D
fails to consider that a tool might not effectively perform its intended function
The author overlooks the possibility that tools might not do what they’re supposed to. Perhaps GIAPS is poorly designed and causes people to make ineffective presentations. This is why the fact GIAPS is a tool does not absolve it of potential responsibility for bad presentations.
E
rejects a claim because of its source rather than its content
The author doesn’t reject the claim of the information expert because of some character/background feature of the expert. The author’s conclusion is based on the fact GIAPS is a tool.

14 comments

Editorial: The legislature is considering allowing oil drilling in the Cape Simmons Nature Preserve. Supporters claim that, because modern drilling methods will be used, there will be no damage to the environment. However, that claim is easily disproven by looking at nearby Alphin Bay, where oil drilling began five years ago. The land there is marred by industrial sprawl, drilling platforms, and thousands of miles of roads and pipelines.

Summarize Argument
The editorialist concludes that, despite using modern drilling methods, oil drilling will cause environmental damage in Cape Simmons Nature Preserve. This claim is backed up by a comparison to an analogous case in Alphin Bay, where drilling which began five years ago has caused significant damage.

Notable Assumptions
The editorialist assumes that Cape Simmons and Alphin Bay are relevantly analogous. In other words, the land in Cape Simmons would suffer similar effects to Alphin Bay. This includes the assumption that modern oil drilling methods were used in Alphin Bay.

A
The Cape Simmons Nature Preserve is one of the few areas of pristine wilderness in the region.
The number of other areas of pristine wilderness in the region is irrelevant to whether the Cape Simmons Nature Preserve will suffer environmental damage from oil drilling.
B
The companies drilling for oil at Alphin Bay never claimed that drilling there would not cause any environmental damage.
Oil drilling companies’ claims about the effects of drilling in Alphin Bay are irrelevant to the editorialist’s argument about the effects of drilling in Cape Simmons.
C
The editorialist believes that oil drilling should not be allowed in a nature preserve unless it would cause no environmental damage.
The editorialist makes no claims about whether oil drilling should or should not be allowed due to causing environmental damage, only whether it will cause environmental damage in the first place.
D
There have been no significant changes in oil drilling methods in the last five years.
This justifies the editorialist’s assumption that the likely effects of oil drilling in Cape Simmons can be predicted from its effects in Alphin Bay, as the same modern drilling methods would be used in both cases.
E
Oil drilling is only one of several industrial activities that takes place at Alphin Bay.
This claim would potentially weaken the argument, as it provides possible alternate explanations for the environmental damage at Alphin Bay—namely, the other industrial activities taking place there. It certainly doesn’t strengthen.

7 comments