Critical Reasoning

During the earliest period of industrialization in Britain, steam engines were more expensive to build and operate than either windmills or water mills, the other practicable sources of power for factories. Yet despite their significant cost disadvantage, steam-powered factories were built in large numbers well before technical improvements brought their cost down. Furthermore, they were built even in regions where geographical conditions permitted the construction of wind- and water-powered factories close to major markets. Which of the following, if true, most helps to explain the proliferation of steam-powered factories during the earliest period of industrialization in Britain?

A popular beach has long had a dolphin-feeding program in which fish are given to dolphins several times a day. Many dolphins get as much as half of their food each day there. Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild. Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?

**Plant scientists have used genetic engineering on seeds to produce crop plants that are highly resistant to insect damage.** Unfortunately, the seeds themselves are quite expensive, and the plants require more fertilizer and water to grow well than normal ones. Accordingly, **for most farmers the savings on pesticides would not compensate for the higher seed costs and the cost of additional fertilizer.** However, since consumer demand for grains, fruits, and vegetables grown without the use of pesticides continues to rise, the use of genetically engineered seeds of this kind is likely to become widespread. In the argument given, the two portions in boldface play which of the following roles?

Leptin, a protein occurring naturally in the blood, appears to regulate how much fat the body carries by speeding up the metabolism and decreasing the appetite when the body has too much fat. Mice that do not naturally produce leptin have more fat than other mice, but they lose fat rapidly when they are given leptin injections. Unfortunately, however, leptin cannot be used as a dietary supplement to control fat, since __________. Which of the following most logically completes the passage?

Large national budget deficits do not cause large trade deficits. If they did, countries with the largest budget deficits would also have the largest trade deficits. In fact, when deficit figures are adjusted so different countries are reliably comparable to each other, there is no such correlation. If the statements above are all true, which of the following can properly be inferred on the basis of them?

Archaeologists use technology to analyze ancient sites. It is likely that this technology will advance considerably in the near future, allowing archaeologists to gather more information than is currently possible. If they study certain sites now, they risk contaminating or compromising them for future studies. Therefore, in order to maximize the potential for gathering knowledge in the long run, a team of archaeologists plans to delay the examination of a newly excavated site. Which of the following would be most useful to investigate for the purpose of evaluating the plan’s prospects for achieving its goal?

More and more law firms specializing in corporate taxes are paid on a contingency-fee basis. Under this arrangement, if a case is won, the firm usually receives more than it would have received if it had been paid on the alternate hourly rate basis. If the case is lost, the firm receives nothing. Most firms are likely to make more under the contingency-fee arrangement. Which of the following, if true, would most strengthen the prediction above?

Pretzel vendor: The new license fee for operating a pretzel stand outside the art museum is prohibitively expensive. Charging typical prices, I would need to sell an average of 25 pretzels per hour to break even. At my stand outside City Hall, with about as many passers-by as at the art museum, I average only 15 per hour. So I could not break even running a stand outside the art museum, much less turn a profit. Which of the following, if true, most seriously weakens the pretzel vendor’s argument?

Beginning in 1966, all new cars sold in Morodia were required to have safety belts and power steering. Previously, most cars in Morodia were without these features. Safety belts help to prevent injuries in collisions, and power steering helps to avoid collisions in the first place. But even though in 1966 one-seventh of the cars in Morodia were replaced with new cars, the number of car collisions and collision-related injuries did not decline. Which of the following, if true about Morodia, most helps to explain why the number of collisions and collision-related injuries in Morodia failed to decline in 1966?

Manufacturers of mechanical pencils make most of their profit on pencil leads rather than on the pencils themselves. The Write Company, which cannot sell its leads as cheaply as other manufacturers can, plans to alter the design of its mechanical pencil so that it will accept only a newly designed Write Company lead, which will be sold at the same price as the Write Company’s current lead. Which of the following, if true, most strongly supports the Write Company’s projection that its plan will lead to an increase in its sales of pencil leads?

Enterprise Bank currently requires customers with checking accounts to maintain a minimum balance or pay a monthly fee. Enterprise plans to offer accounts with no monthly fee and no minimum-balance requirement; to cover their projected administrative costs of $\$3$ per account per month, they plan to charge $\$30$ for overdrawing an account. Since each month on average slightly more than 10 percent of Enterprise’s customers overdraw their accounts, bank officials predict the new accounts will generate a profit. Which of the following, if true, most strongly supports the bank officials’ prediction?

Highway official: When resurfacing our concrete bridges, we should use electrically conductive concrete (ECC) rather than standard concrete. In the winter, ECC can be heated by passing an electric current through it, thereby preventing ice buildup. The cost of the electricity needed is substantially lower than the cost of the deicing salt we currently use. Taxpayer: But ECC is vastly more expensive than standard concrete, so your proposal is probably not justifiable on economic grounds. Which of the following, if true, could best be used by the highway official to support the official’s proposal in the face of the taxpayer’s objection?

In virtually any industry, technological improvements increase labor productivity, which is the output of goods and services per person-hour worked. In Parland’s industries, labor productivity is significantly higher than it is in Vergia’s industries. Clearly, therefore, Parland’s industries must, on the whole, be further advanced technologically than Vergia’s are. The argument is most vulnerable to which of the following criticisms?

Chaco Canyon, a settlement of the ancient Anasazi culture in North America, had massive buildings. **It must have been a major Anasazi center.** Analysis of wood samples shows that some of the timber for the buildings came from the Chuska and San Mateo mountains, 50 miles from Chaco Canyon. **Only a major cultural center would have the organizational power to import timber from 50 miles away.** In the argument given, the two portions in boldface play which of the following roles?

Paper and plastic grocery bags are a continuing problem for the city, both as litter and in landfills. To discourage their use, the city council has proposed a tax on each bag to be paid by the supermarkets that supply them. Several environmental groups, however, oppose the tax despite having brought the issue to the council’s attention in the first place. Which of the following, if true, would best explain the environmental groups’ opposition to the proposed tax?

Regulations will not allow a pesticide that is toxic to humans to be used inside houses unless the pesticide will dissipate completely from the air within eight hours after its application. One test pesticide manufacturers typically use to determine how quickly anti-termite pesticides dissipate involves spraying the pesticides on the walls of room-sized plywood boxes and then timing their dissipation. Which of the following would it be most useful to know in order to evaluate whether a dissipation time of just under eight hours on the manufacturers’ test indicates an anti-termite pesticide that is toxic to humans obeys regulations for use in houses?

In a typical year, Innovair’s airplanes are involved in 35 collisions while parked or being towed in airports, with a resulting yearly cost of $\$1,000,000$ for repairs. To reduce the frequency of ground collisions, Innovair will begin giving its ground crews additional training, at an annual cost of $\$500,000$. Although this will cut the number of ground collisions by about half at best, the drop in repair costs can be expected to be much greater, since __________. Which of the following most logically completes the argument?

Many agriculturally intensive areas of the world are beginning to encounter water scarcity problems. As a result, many farmers in these areas are likely to reduce their output as the water supply they need in order to maintain production shrinks. However, one group of farmers in such a region plans to increase their production by implementing techniques for water conservation. Which of the following, if true, would most strongly support the prediction that the group’s plan will succeed?

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?

Because the cork stoppers in wine bottles can leak, crumble, or become moldy, winemakers must often discard a significant proportion of their inventory of bottled wine. Bottlemaster, Inc., produces a plastic stopper that cannot leak, crumble, or mold. **Bottlemaster’s plastic stopper is available to winemakers for a price only slightly higher than that of traditional cork stoppers**, and cork prices are expected to rise considerably in the near future. Therefore, **Bottlemaster’s plastic stopper will increase its share of the market for wine-bottle stoppers**. In the argument given, the two portions in boldface play which of the following roles?