Critical Reasoning

Scientists propose placing seismic stations on the floor of the Pacific Ocean to warn threatened coastal communities on the northwestern coast of the United States of approaching tidal waves caused by earthquakes. Since forewarned communities could take steps to evacuate, many of the injuries and deaths that would otherwise occur could be avoided if the government would implement this proposal. The answer to which of the following questions would be most important in determining whether implementing the proposal would be likely to achieve the desired result?

Last year a chain of fast-food restaurants, whose menu had always centered on hamburger, added its first vegetarian sandwich, much lower in fat than the chain�s other offerings. Despite heavy marketing, the new sandwich accounts for a very small proportion of the chain�s sales. The sandwich�s sales would have to quadruple to cover the costs associated with including it on the menu. Since such an increase is unlikely, the chain would be more profitable if it dropped the sandwich. Which of the following, if true, most seriously weakens the argument?

Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska, is known to be 11,200 years old. Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago. Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?

Although the discount stores in Goreville central shopping district are expected to close within five years as a result of competition from a SpendLess discount department store that just opened, those locations will not stay vacant for long. In the five years since the opening of Colson's, a nondiscount department store, a new store has opened at the location of every store in the shopping district that closed because it could not compete with Colson's. Which of the following, if true, most seriously weakens the argument?

A company that manufactures plastic products from recyclable plastic is, surprisingly, unconcerned that economic conditions may worsen, despite analysts' belief that consumers would then consider ecofriendly plastic products an expensive luxury. But the company reasons that it will be able to lower its prices because, in a weakened economy, other ecofriendly plastic manufacturers are likely to fail. Demand among manufacturers for recyclable plastics as raw materials would then plummet, creating an oversupply of such materials, making them less expensive for the manufacturer to purchase and thus lowering the company's costs. B Some retailers whose sales include various companies' ecofriendly plastic products have struggled in recent years despite the overall good economy. C Consumers would likely soon learn of the oversupply of recyclable plastics and cease recycling them, significantly raising manufacturers' raw-material costs. D Retailers, including retailers that cater to consumers seeking certain types of ecofriendly products, may lose some business if economic conditions worsen. E The plastics used by the company in its products were, after a recent investigation by a regulatory body, declared to be safe for consumers.

Veterinarians generally derive some of their income from selling several manufacturers' lines of pet-care products. Knowing that pet owners rarely throw away mail from their pet's veterinarian unread, one manufacturer of pet-care products offered free promotional materials on its products to veterinarians for mailing to their clients. Very few veterinarians accepted the offer, however, even though the manufacturer's products are of high quality. Which of the following, if true, most helps to explain the veterinarian's reaction to the manufacturer's promotional scheme?

For the period from the eighth century through the eleventh century, the shifting boundaries between Kingdom F and Kingdom G have not been well charted. Although a certain village in a border region between the two kingdoms usually belonged to Kingdom G, ninth-century artifacts found in the village were in the typical Kingdom F style of that time. It is unclear whether the village was actually a part of Kingdom F in the ninth century or whether it was a part of Kingdom G but had merely adopted Kingdom F's artistic styles under Kingdom F's cultural influence. Which of the following would, if found in ninth-century sites in the village, best help in determining whether the village was a part of Kingdom F or Kingdom G in the ninth century?

Mayor: False alarms from home security systems waste so much valuable police time that in many communities police have stopped responding to alarms from homes whose systems frequently produce false alarms. This policy reduces wastage of police time but results in a loss of protection for some residents. To achieve a comparable reduction in wastage without reducing protection for residents, the council has enacted a measure to fine residents for repeated false alarms. Which of the following, if true, casts the most doubt on whether the measure enacted by the council will achieve its goal?

In parts of the Caribbean, the manatee, an endangered marine mammal, has long been hunted for its meat. Having noted the manatee hunters� expert knowledge of manatees� habits, local conservationists are encouraging the hunters to stop hunting and instead to take tourists on boat rides to see manatees. Tourist interest is high, so the plan has promise of achieving the twin goals of giving the former hunters a good income and helping ensure the manatees� survival. Which of the following, if true, raises the most serious doubt about the plan�s chance of success?

An unusually severe winter occurred in Europe after the continent was blanketed by a blue haze resulting from the eruption of the Laki Volcano in the European republic of Iceland in the summer of 1984. Thus, it is evident that major eruptions cause the atmosphere to become cooler than it would be otherwise. Which of the following statements, if true, most seriously weakens the argument above?

The Testament of William Thorpe was published around 1530 as an appendix to Thorpe's longer Examination. Many scholars, however, doubt the attribution of the Testament to Thorpe because, whereas the Examination is dated 1406, the Testament is dated 1460. One scholar has recently argued that the 1460 date be amended to 1409, based on the observation that when these numbers are expressed as Roman numerals, MCCCCLX and MCCCCIX, it becomes easy to see how the dates might have become confused through scribal error. Which of the following, if true, would most support the scholar's hypothesis concerning the date of the Testament?

Professor: A marine biologist argues that transmission of sea lice from farm salmon to wild salmon is unlikely in the Broughton Archipelago, British Columbia, citing numerous studies suggesting that salinities less than 30 parts per thousand are unfavorable to sea-lice survival. The biologist concludes that the archipelago's 25�30 parts per thousand salinity range between March and June, the critical period for wild salmon migration, tends to suppress sea-lice proliferation. But a review of the literature shows that salinities of 25�30 parts per thousand in combination with British Columbia's cool spring temperatures favor the flourishing of sea lice. In this passage, the professor attempts to undermine the biologist's argument by

The country of Virodia has, until now, been barely self-sufficient in both meat and grain. Greater prosperity there has gone hand in hand with steadily increasing per capita consumption of meat, and it takes several pounds of grain used as feed to produce one pound of meat. Per capita income is almost certain to rise further, yet increases in domestic grain production are unlikely. Which of the following is most strongly supported by the information given?

Which of the following most logically completes the passage? The figures in portraits by the Spanish painter El Greco (1541�1614) are systematically elongated. In El Greco�s time, the intentional distortion of human figures was unprecedented in European painting. Consequently, some critics have suggested that El Greco had an astigmatism, a type of visual impairment, that resulted in people appearing to him in the distorted way that is characteristic of his paintings. However, this suggestion cannot be the explanation, because______________.

Which of the following most logically completes the passage? Laminated glass is much harder to break than the glass typically used in the windows of cars driven in Relnia. It is more difficult for thieves to break into cars with laminated glass windows than into cars with ordinary glass windows, and laminated glass windows are less likely to break in a collision. Nevertheless, considerations of security and safety do not unambiguously support a proposal to require that in Relnia all glass installed in cars be laminated glass, since __________.

Supply shortages and signs of growing demand are driving cocoa prices upward. Unusually severe weather in cocoa-producing regions�too much rain in Brazil and too little in West Africa�has limited production. Further, Europe and North America recently reported stronger demand for cocoa. In the first quarter, grinding of cocoa beans�the first stage in processing cocoa for chocolate�rose 8.1 percent in Europe and 16 percent in North America. Analysts have concluded that cocoa's price will continue to rise at least into the near future. Which of the following would, if true, most strengthen the reasoning above?

Many people suffer an allergic reaction to certain sulfites, including those that are commonly added to wine as preservatives. However, since there are several winemakers who add sulfites to none of the wines they produce, people who would like to drink wine but are allergic to sulfites can drink wines produced by these winemakers without risking an allergic reaction to sulfites. Which of the following is an assumption on which the argument depends?

Many industrialized nations are trying to reduce atmospheric concentrations of carbon dioxide, a gas released by the burning of fossil fuels. One proposal is to replace conventional cement, which is made with calcium carbonate, by a new �eco-cement.� This new cement, made with magnesium carbonate, absorbs large amount of carbon dioxide when exposed to the atmosphere. Therefore, using eco-cement for new concrete building projects will significantly help reduce atmospheric concentrations of carbon dioxide. Which of the following, if true, most strengthens the argument?

Only a reduction of 10 percent in the number of scheduled flights using Greentown's airport will allow the delays that are so common there to be avoided. Hevelia airstrip, 40 miles away, would, if upgraded and expanded, be an attractive alternative for fully 20 percent of the passengers using Greentown airport. Nevertheless, experts reject the claim that turning Hevelia into a full-service airport would end the chronic delays at Greentown. Which of the following, if true, most helps to justify the experts' position?

Increased use of incineration is sometimes advocated as a safe way to dispose of chemical waste. But opponents of incineration point to the 40 incidents involving unexpected releases of dangerous chemical agents that were reported just last year at two existing incinerators commissioned to destroy a quantity of chemical waste material. Since designs for proposed new incinerators include no additional means of preventing such releases, leaks will only become more prevalent if use of incineration increases. Which of the following, if true, most seriously weakens the argument?