Columnist: Much of North America and western Europe is more heavily forested and has less acid rain and better air quality now than five decades ago. Though this may be due largely to policies advocated by environmentalists, it nonetheless lends credibility to the claims of people who reject predictions of imminent ecological doom and argue that environmental policies that excessively restrict the use of natural resources may diminish the wealth necessary to adopt and sustain the policies that brought about these improvements.

Summarize Argument
People claim that excessively restrictive policies on natural resources make it financially difficult to adopt and sustain environmental policies. Their evidence is that North American and western Europe are more heavily forested and have better air quality than 50 years ago.

Notable Assumptions
The people in question assume that North America and western Europe not only didn’t adopt restrictive policies on natural resources in the last 50 years, but that North America and western Europe also implemented effective environmental policies that relied on wealth. If clean air and forestation somehow came in spite of government policies, then these people wouldn’t have a very convincing argument.

A
Nations sustain their wealth largely through industrial use of the natural resources found within their boundaries.
If nations restrict their natural resource use, they restrict their primary source of wealth. Thus, restrictive laws on natural resource use absolutely would diminish nations’ wealth.
B
The more advanced the technology used in a nation’s industries, the greater is that nation’s ability to devote a portion of its resources to social programs.
We don’t care about technology. This doesn’t factor into the argument.
C
A majority of ecological disasters arise from causes that are beyond human control.
We don’t care about ecological disasters. We’re talking about the ecological damage governments can control through policy.
D
If a compromise between the proponents of economic growth and the environmentalists had been enacted rather than the current policies, the environment would have seen significantly less improvement.
We have no idea what that compromise would look like. Nor do we know what policies environmentalists advocated for.
E
The concern demonstrated by a nation for the health and integrity of its natural ecosystems leads to an increase in that nation’s wealth.
This relationship doesn’t appear in the argument. The causal relationship is: more wealth causes more environmental protection.

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There is evidence to suggest that our cave-dwelling ancestors polished many of their flints to a degree far surpassing what was necessary for hunting purposes. It seems, therefore, that early humans possessed an aesthetic sense.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that early humans could appreciate aesthetics. This is shown by the phenomenon that early humans often polished stones more than was needed for hunting purposes.

Notable Assumptions
The author assumes that the only reason early humans would polish flints beyond what was necessary for hunting is to appreciate the aesthetics of the highly polished stones. The author further assumes that there are no other explanations for this degree of polishing.

A
Most flints used by our cave-dwelling ancestors were not highly polished.
This does not affect the argument. The premise states that “many” of the early humans’ flints were highly polished; most of them not being highly polished is compatible with the argument.
B
The caves in which the highly polished flints were found are unadorned by cave paintings.
This does not affect the argument. A lack of cave paintings does not undermine the idea that early humans possessed an aesthetic sense—perhaps they appreciated the aesthetics of highly polished flints but did not care for the aesthetics of cave paintings.
C
There is evidence that these highly polished flints were used for display in religious ceremonies.
This strengthens the argument. If the purpose of the highly polished flints was for display in religious ceremonies, early humans must have had an aesthetic sense that motivated them to polish the flints for this purpose.
D
Flints were often used by early humans for everyday chores other than hunting.
This weakens the argument by offering an alternative explanation for the described phenomenon. The highly polished flints—while not necessary for hunting—could have been used in everyday chores. This explanation gives no reason to suggest that early humans had an aesthetic sense.
E
Any benefits that an aesthetic sense would have given to cave-dwelling humans are poorly understood.
This does not affect the argument. Our poor understanding of the benefits early humans could have derived from an aesthetic sense does not undermine the assertion that they may nevertheless have possessed an aesthetic sense.

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The statements above, if true, most strongly support which one of the following?

This is a Most Strongly Supported question.

Gene splicing can give rise to new varieties of farm animals that have only a partially understood genetic makeup.

This statement tells us a fact about gene splicing – it might give rise to new kinds of farm animals with genetics we don’t fully understand. Genetically mysterious super-cows? Weirdly buff chickens with six-pack abs? Let’s see where this is going.

In addition to introducing the genes for whichever trait is desired, the technique can introduce genes governing the production of toxins or carcinogens, and these latter undesirable traits might not be easily discoverable.

Apparently gene-splicing can introduce genes that control the production of poisons and cancer-causing substances. In addition, it can be difficult to detect “these … undesirable traits” – this is a reference to the production of poisons and cancer-causing substances. It seems that gene-splicing might, for example, make a cow produce stuff that’s poisonous or causes cancer. And we might have a difficult time realizing that the genetically modified cow produces this stuff.

The stimulus doesn’t lend itself to any specific prediction – let’s go to the answers and look for what’s most strongly supported.

Answer Choice (A) All toxin production is genetically controlled.

“All” toxin production? We know that some toxin production is affected by genes. But we can’t infer that every single kind of toxin production is genetically controlled. That would be the logical flaw of hasty generalization.

Correct Answer Choice (B) Gene splicing to produce new varieties of farm animals should be used cautiously.

This answer contains “should,” which makes it a normative claim. These kinds of claims are inherently more difficult to support. However, there is enough in the stimulus to suggest that we should be cautious about gene splicing – we know that this technique can produce “undesirable” traits in farm animals, and that these traits can be difficult to detect. Calling those traits undesirable means that we don’t want to produce those traits in farm animals – so that’s a reason to be cautious about gene splicing. It produces something that we don’t want and we might not discover the problem easily.

Answer Choice (C) Gene splicing is not effective as a way of producing new varieties of farm animals.

We can’t speak to how effective gene splicing is at producing new farm animals. We know that it can produce new farm animals. But is this a highly effective technique? Minimally effective? The stimulus doesn’t say any more about this.

Make sure not to conflate the effectiveness of gene splicing with the desirability or wisdom of gene splicing. The stimulus does give us facts that would suggest we might not want to engage in gene splicing. But that’s a separate question from whether gene splicing is effective at creating new farm animals or not.

Answer Choice (D) Most new varieties of farm animals produced by gene splicing will develop cancer.

“Most” means over half. The stimulus doesn’t support a claim about over half of new farm animals with respect to developing cancer.

Even if this answer had said “some” at the beginning, it still would not be supported. We know gene splicing can lead to a trait governing production of cancer-causing substances. But that doesn’t imply the animals with these traits will develop cancer – maybe the concern is that people will get cancer from consuming these farm animals or drinking their milk.

Answer Choice (E) Gene splicing will advance to the point where unforeseen consequences are no longer a problem.

Why is this answer so optimistic? The stimulus didn’t give us any evidence about what will happen in the future with gene splicing. This answer is trying to tempt you based on your real-world assumption that science and technology constantly develop. But we don’t know what, if anything, will happen with gene splicing. Maybe scientists will be stumped and can’t make any more progress at reducing or eliminating side effects of gene splicing.


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Gene splicing can give rise to new varieties of farm animals that have only a partially understood genetic makeup. In addition to introducing the genes for whichever trait is desired, the technique can introduce genes governing the production of toxins or carcinogens, and these latter undesirable traits might not be easily discoverable.

Summary
Gene splicing can create new kinds of farm animals whose genetic makeup is only partially understood. While the process can introduce desired traits, it can also introduce potentially harmful genes that are difficult to detect.

Strongly Supported Conclusions
Gene splicing can have some negative unintended consequences.

A
All toxin production is genetically controlled.
This is too strong to support. The stimulus gives support that *some* toxin production is genetically controlled, not “all.”
B
Gene splicing to produce new varieties of farm animals should be used cautiously.
The stimulus claims that genetic splicing can bring about “undesirable” traits. Thus, it is reasonable that the statements support being “cautious” about the technique.
C
Gene splicing is not effective as a way of producing new varieties of farm animals.
This statement is too strong to support. The stimulus only says that it has some undesirable consequences, not that it is “not effective.”
D
Most new varieties of farm animals produced by gene splicing will develop cancer.
There is no mention of cancer in the stimulus. You need a lot of assumptions to make this work
E
Gene splicing will advance to the point where unforeseen consequences are no longer a problem.
There is no support for what gene splicing will look like in the future.

51 comments

Astronauts who experience weightlessness frequently get motion sickness. The astronauts see their own motion relative to passing objects, but while the astronauts are weightless their inner ears indicate that their bodies are not moving. The astronauts’ experience is best explained by the hypothesis that conflicting information received by the brain about the body’s motion causes motion sickness.

Summarize Argument: Phenomenon-Hypothesis
The author concludes that motion sickness is caused by the brain receiving conflicting information about the body’s motion.

Notable Assumptions
The author assumes that conflicting information rather than some other phenomenon that astronauts experience in space is responsible for motion sickness. This same phenomenon of conflicting information should thus be applicable on earth, as well.

A
During rough voyages ship passengers in cabins providing a view of the water are less likely to get motion sickness than are passengers in cabins providing no view.
If the passengers can’t see the water, then they wouldn’t be receiving conflicting information. Since these passengers are less likely to get motion sickness, it would seem the cause really is conflicting information.
B
Many people who are experienced airplane passengers occasionally get motion sickness.
We don’t care about occasional motion sickness. Besides, we have no idea if planes feature the same “conflicting information” phenomenon as space shuttles.
C
Some automobile passengers whose inner ears indicate that they are moving and who have a clear view of the objects they are passing get motion sickness.
The author never says conflicting information is the only way motion sickness occurs. It’s simply the explanation for how motion sickness occurs for austronauts.
D
People who have aisle seats in trains or airplanes are as likely to get motion sickness as are people who have window seats.
This would seem to strengthen the author’s argument, but we have no idea if people who sit in window seats are looking out the windows and getting conflicting information. (A) closes that ambiguity.
E
Some astronauts do not get motion sickness even after being in orbit for several days.
The author never says all astronauts get motion sickness. She simply explains what probably causes motion sickness for astronauts.

47 comments