At a certain?period in Earth’s history, its atmosphere contained almost no oxygen, although plants were producing vast quantities of oxygen. As a way of reconciling these two facts, scientists have hypothesized that nearly all of the oxygen being produced was taken up by iron on Earth’s surface. Clearly, however,?this explanation is inadequate.?New studies show that?the amount of iron on Earth’s surface was not sufficient to absorb anywhere near as much oxygen as was being produced.?Therefore, something in addition to the iron on Earth’s surface must have absorbed much of the oxygen produced by plant life.

?1. In the argument given, the two portions in boldface play which of the following roles?

A. The first is a claim made by the argument in support of a certain position; the second is that position.

B. The first is a judgment made by the argument about a certain explanation; the second is that explanation.

C. The first expresses the argument’s dismissal of an objection to the position it seeks to establish; the second is that position.

D. The first sums up the argument’s position with regard to a certain hypothesis; the second provides grounds for that position.

E. The first is a concession by the argument that its initial formulation of the position it seeks to establish requires modification; the second presents that position in a modified form.

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Rain-soaked soil contains less oxygen than does drier soil.?The roots of melon plants perform less efficiently under the low-oxygen conditions present in rain soaked soil.?When the efficiency of melon roots is impaired, the roots do not supply sufficient amounts of the proper nutrients for the plants to perform photosynthesis at their usual levels. It follows that?melon plants have a lower-than-usual rate of photosynthesis when their roots are in rain-soaked soil.?When the photosynthesis of the plants slows, sugar stored in the fruits is drawn off to supply the plants with energy. Therefore, ripe melons harvested after a prolonged period of heavy rain should be less sweet than other ripe melons.

?2. In the argument given, the two portions in boldface play which of the following roles?

A. The first states the conclusion of the argument as a whole; the second provides support for that conclusion.

B. The first provides support for the conclusion of the argument as a whole; the second provides evidence that supports an objection to that conclusion.

C. The first provides support for an intermediate conclusion that supports a further conclusion stated in the argument; the second states that intermediate conclusion.

D. The first serves as an intermediate conclusion that supports a further conclusion stated in the argument; the second states the position that the argument as a whole opposes.

E. The first states the position that the argument as a whole opposes; the second supports the conclusion of the argument.

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Columnist: Until very recently, Presorbin and Veltrex, two medications used to block excess stomach acid, were both available only with a prescription written by a doctor. In an advertisement for Presorbin, its makers argue that?Presorbin is superior?on the grounds that doctors have written 200 million prescriptions for Presorbin, as compared to 100 million for Veltrex. It can be argued that the number of prescriptions written is never a worthwhile criterion for comparing the merits of medicines, but that?the advertisement’s argument is absurd?is quite adequately revealed by observing that Presorbin was available as a prescription medicine years before Veltrex was.

?3. In the columnist’s argument,?the two highlighted portions?play which of the following roles?

A. The first is a claim that the columnist’s argument seeks to clarify; the second states a conclusion drawn about one possible interpretation of that claim.

B. The first identifies the conclusion of an argument that the columnist’s argument is directed against; the second states the main conclusion of the columnist’s argument.

C. The first states the main conclusion of the columnist’s argument; the second states a conclusion that the columnist draws in defending that conclusion against an objection.

D. The first identifies an assumption made in an argument that the columnist's argument is directed against; the second states the main conclusion of the columnist’s argument.

E. The first is a claim that has been offered as evidence to support a position that the columnist opposes; the second states the main conclusion of the columnist’s argument.

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The number of traffic deaths in our region has increased over the past several years.?Because the poor condition of our roads and highways has caused a number of fatal accidents, the road commission recommended that, to reduce traffic deaths, the budget for road maintenance should be increased.?Many major traffic deaths, however, are attributed to traffic congestion than to poor road condition, and better road will encourage people to drive more, worsen traffic congestion. So a better strategy for the road commission to recommend would be to reduce traffic congestion, though the best means for doing so remains to be determined. Improving mass transit is only one possibility.

?4. In the politician’s argument,?the two highlighted portions?play which of the following roles?

A. The first introduce the position that the politician seeks to establish, the second provides evidence to support that position.

B. The first introduces the position that the politician seeks to establish, the second is evidence that was cited in support of the position that the politician opposes.

C. The first introduces the position that the politician seeks to establish, the second is an intermediate conclusion that is made in order to support that position.

D. The first introduces a problem, the response to which is presented in the argument, the second provides evidence that is aimed at arguing that a proposed response to this problem will turn out to be counterproductive.

E. The first introduces a problem, the response to which is presented in the argument, the second is evidence that was cited in support of a response that the politician opposes.

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Stylistic evidence and laboratory evidence strongly support the claim that the magnificent painting Garden of Eden?is a work of the Flemish master van Eyck. Nevertheless,?the painting must have been the work of someone else,?as anyone with a little historical and zoological knowledge can tell merely by looking at the painting.?The animals in the painting are all vivid representations of actual animals, including armadillos.?Yet armadillos are native only to Americas, and van Eyck died decades before Europeans reached the Americas.

?5. In the argument given, the two highlighted portions play which of the following roles?

A. The first is a position that the argument seeks to reject, the second is evidence that the argument uses against that position.

B. The first and the second are each pieces of evidence that have been used to support the position that the argument opposes.

C. The first presents the main conclusion of the argument; the second provides evidence in support of that conclusion.

D. The first is a judgment that serves as the basis for the main conclusion of the argument; the second states that main conclusion.

E. The first is an intermediate conclusion drawn in order to support a further conclusion stated in the argument; the second provides evidence in support of that intermediate conclusion.

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In most coastal regions, the level of the sea is rising in relation to the land by one to two millimeters a year, and this trend would be explained by the hypothesis that at the North and South Poles, the amount of ice that melts during the summer now exceeds the amount forms during the winter. The hypothesis is not undermined by observations that?sea levels are falling relative to the Scandinavian coast by four millimeters a year.?Much land in northern latitudes, including Scandinavia, is still rising in response to being freed of the enormous weight of the ice that used to cover it during the last ice age, and?in Scandinavia the land is now rising faster than the sea.

?6. In the passage, the two highlighted portions play which of the following roles?

A. The first states observations the accuracy of which is challenged in the passage; the second is part of the ground on which that challenge is based.

B. The first states observations that, according to the passage, are incompatible with a certain hypothesis; the second is part of the grounds offered in support of a revision of that hypothesis.

C. The first states observations that, according to the passage, can be reconciled with a certain hypothesis; the second describes a phenomenon that is the factual basis of that reconciliation.

D. The first presents a phenomenon, two competing explanations of which are considered in the passage; the second is the explanation of the phenomenon that the passage argues is correct.

E. The first provides evidence against a position; the second is that position.

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Editors of major United States newsmagazines have been criticized for reducing the amount of space these magazines devote to international news. According to these editors, however, readers are wholly to blame for the reductions. After all, the editors point out,?sales of magazine issues that prominently feature international news stories have declined significantly,?and declining sales reflect declining reader interest. Yet even if true, this evidence does not refute the contention that editors should bear some of the blame for the reductions, unless editors are merely passive instruments responding to reader interest. And that is clearly an untenable view, since?editors can often intensify readier interest in a news topic by giving it frequent coverage.

?7. In the argument as a whole, the two highlighted portions play which of the following roles?

A. The first is evidence that has been used to support a position that the argument opposes; the second is a point that the argument raises to cast doubt on the reasoning used to support that position.

B. The first presents a claim, the truth of which is evaluated in the argument, the second is information introduced to cast doubt on that claim.

C. The first presents a claim, the truth of which is evaluated in the argument, the second provides evidence in support of that claim

D. The first cites evidence in support of the main conclusion of the argument, the second states that conclusion

E. The first states an assumption that is explicitly made to support the main conclusion of the argument, the second is a position that the argument as a whole opposes.

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In the country of Seligia, where asbestos have been used extensively in construction, that use is about to be banned, because the exposure of construction workers to asbestos can cause a certain type of cancer. We can predict that?the ban will result in reducing the incidence of that type of cancer in Seligia by as much as 50 percent.

It is true that?no more than 30 percent of the death certificates of Seligians who have died of that cancer have “constructions” listed as the deceased’s occupation.?The cancer takes about 2- years after exposure to develop, however, and Seligians who have worked in construction commonly turn to less strenuous occupations as they age. Slogan death certificates indicate only the deceased’s last occupation.

?8. In the argument given, the two highlighted portions play which of the following roles?

A. the first is a prediction that the argument seeks to defend; the second presents evidence that if not supplemented would cast doubt on that judgment.

B. the first is a prediction that the argument seeks to defend; the second is a finding, the accuracy of which is disputed by the argument as a whole.

C. the first is a prediction that the argument as a whole rejects; the second presents evidence on which that rejection is based.

D. the first is a prediction that the argument as a whole seeks to defend; the second is evidence that the defense can be at best partly successful.

E. the first is a prediction that is cited in order to justify a stated conclusion; the second is a consideration that has been raised against that conclusion.

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Cuts that need to be held closed in order to heal properly have generally been held closed with stitches.?However, pressure to reduce medical costs is mounting. Consequently, it is likely that a newly developed adhesive will become the routine method of holding most types of cuts closed. The new adhesive holds most types of cuts closed as well as stitches do, and the cost of applying it is comparable to that of closing cuts with stitches. But whereas stitches must generally be removed by medical personnel after the cut has healed, the adhesive simply wears off.?Thus, for any cut that the adhesive can hold closed as well as stitches can, it is more economical to use the adhesive.

?9. In the argument given, the two highlighted portions play which of the following roles?

A. The first is a claim that the argument disputes; the second provides evidence against that disputed claim.

B. The first is a claim that is used as supporting evidence for the main conclusion of the argument; the second is that main conclusion.

C. The first is a claim that is used as supporting evidence for the main conclusion of the argument; the second is a conclusion that is drawn in order to support that main conclusion.

D. The first introduces a practice about which the argument makes a prediction, the second is a conclusion based on that prediction.

E. The first introduces a practice about which the argument makes a prediction; the second is an assessment that is used to support that prediction.

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The traditional color of fire trucks is red, but in cities that have introduced yellow trucks into their fleets, the rate of traffic accidents per mile driven among these trucks has been far lower than the rate among red trucks. Some critics of the innovation have questioned whether?this difference should be attributed to color, given that the yellow trucks were generally newer than the red trucks with which they were compared. But this criticism can be dismissed. Certainly,?the mere difference in accident rates is not decisive evidence.?The decisive fact is that the rates differed significantly only in the hours around dawn and dusk. At these hours, the visibility of yellow is known to be better than that of red.

?10. In the argument given, the two highlighted portions play which of the following roles?

A. The first is a statement of the position the argument as a whole opposes, the second is a statement of the position it defends.

B. The first is a claim that the argument as a whole calls into question, the second denies the rationale presented by some critics of that claim.

C. The first is a claim that the argument as a whole calls into question, the second points out an error of reasoning made by defenders of that claim.

D. The first is the position defended in the argument; the second is an intermediate conclusion drawn to support that position.

E. The first is the position defended in the argument; the second concedes a point to critics of that position.

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Archaeologists recently excavated a collection of copper tools from a grave in India. Although the tools were similar to others from the same culture, each tool found in the grave was significantly larger than any other known tool of the corresponding type produced by the same culture. Since the larger size would have made many of the tools extremely unwieldy,?the tools were probably made specifically for ceremonial burial.?Tools made for ceremonial burial would be expected to have none of the wear that comes from use, and?indeed these tools showed no such wear.

?11. In the argument given, the two highlighted portions play which of the following roles?

A. The first is introduced as evidence that apparently supports a position the argument opposes, the second is that position.

B. The first is introduced as evidence that apparently supports a position the argument opposes, the second is the position the argument seeks to support.

C. The first is the position the argument seeks to support, the second provides evidence to support that position.

D. The first provides evidence for the position the argument seeks to support, the second is a position that the argument seeks to disprove.

E. The first provides evidence for the position the argument seeks to support, the second is that position.

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