11.An overly centralized economy， not the changes in the climate， is responsible for the poor agricultural production in Country X since its new government came to power. Neighboring Country Y has experienced the same climatic conditions， but while agricultural production has been falling in Country X， it has been rising in Country Y.
Which of the following， if true， would most weaken the argument above？
（A） Industrial production also is declining in Country X.
（B） Whereas Country Y is landlocked， Country X has a major seaport.
（C） Both Country X and Country Y have been experiencing drought conditions.
（D） The crops that have always been grown in Country X are different from those that have always been grown in Country Y.
（E） Country X‘s new government instituted a centralized economy with the intention of ensuring an equitable distribution of goods.
12.Manager： Accounting and Billing are located right next to each other and the t-wo departments do similar kinds of work； yet expenditures for clerical supplies charged to Billing are much higher. Is Billing wasting supplies？ Head of Billing： Not at all.
Which of the following， if true， best supports the position of the Head ofBilling？
（A） There are more staff members in Accounting than in Billing.
（B） Two years ago， expenditures in Accounting for clerical supplies were the same as were expenditures that year in Billing for clerical supplies.
（C） The work of Billing now requires a wider variety of clerical supplies than it did in the past.
（D） Some of the paper-and-pencil work of both Accounting and Billing has been replaced by work done on computers.
（E） Members of Accounting found the clericalsupplies cabinet of Billing more convenient to go to for supplies than their own department‘s cabinet.
13.Some anthropologists study modern-day societies of foragers in an effort to learn about our ancient ancestors who were also foragers. A flaw in this strat-egy is that forager societies are extremely varied. Indeed， any forager society with which anthropologists are familiar has had considerable contact with mo-dern nonforager societies.
Which of the following， if true， would most weaken the criticism made above of the anthropologists‘ strategy？
（A） All forager societies throughout history have had a number of important features in common that are absent from other types of societies.
（B） Most ancient forager societies either dissolved or made a transition to another way of life.
（C） All anthropologists study one kind or another of modern-day society.
（D） Many anthropologists who study modern-day forager societies do not draw inferences about ancient societies on the basis of their studies.
（E） Even those modern-day forager societies that have not had significant contact with modern societies are importantly different from ancient forager societies.
14.In a study of the effect of color on productivity，50 of 100 factory workers were moved from their drab workroom to a brightly colored workroom.Both these workers and the 50 who remained in the drab workroom increased their prod-uctivity， probably as a result of the interest taken by researchers in the work of both groups during the study.Which of the following， if true， would cast most doubt upon the author‘s inter-pretation of the study results given above？
（A） The 50 workers moved to the brightly colored room performed precisely the same manufacturing task as the workers who remained in the drab workroom.
（B） The drab workroom was designed to provide adequate space for at most 65 workers.
（C） The 50 workers who moved to the brightly colored workroom were matched as closely as possible in age and level of training to the 50 workers who remained in the drab work-room.
（D） Nearly all the workers in both groups had volunteered to move to the brightly colored workroom.
（E） Many of the workers who moved to the brightly colored workroom reported that they liked the drab workroom as well as or better than they liked the brightly colored workroom.
15.A researcher discovered that people who have low levels of immune-system activity tend to score much lower on tests of mental health than do people with normal or high immune-system activity. The researcher concluded from this experiment that the immune system protects against mental illness as well as against physical disease.
The researcher‘s conclusion would be most seriously weakened if it were true that
（A） there was a one-year delay between the completion of a pilot study for the experiment and the initiation of the experiment itself.
（B） people‘s levels of immune-system activity are not affected by their use of medications.
（C） a few people with high immune-system activity had scores on the test of mental health that were similar to the scores of people who had normal immune-system activity.
（D） people who have low immune-system activtiy tend to contract more viral infections than do people with normal or high immune-system activitiy.
（E） high levels of stress first cause mental illness and then cause decreased immune-system activitiy in normal individuals
16.A researcher studying drug addicts found that， on average， they tend to manipulate other people a great deal more than nonaddicts do. The researcher concluded that people who frequently manipulate other people are likely to become addicts.
Which of the following， if true， most seriously weakens the researcher‘s conclusion？
（A） After becoming addicted to drugs， drug addicts learn to manipulate other people as a way of obtaining drugs.
（B） When they are imprisoned， drug addicts often use their ability to manipulate other people to obtain better living conditions.
（C） Some nonaddicts manipulate other people more than some addicts do.
（D） People who are likely to become addicts exhibit unusual behavior patterrns other than frequent manipulation of other people.
17.Advertisement：For sinus pain， three out of four hospitals give their patients Novex So when you want the most effective painkiller for sinus pain， Novex is the one to choose.
Which of the following， if true， most seriously ndermines the advertisement‘s argument？
（A） Some competing brands of painkillers are intended to reduce other kinds of pain in addition to sinus pain.
（B） Many hospitals that do not usually use Novex will do so for those patients who cannot tolerate the drug the hospitals usually use.
（C） Many drug manufacturers increase sales of their products to hospitals by selling these products to the hospitals at the lowest price the manufacturers can afford.
（D） Unlike some competing brands of painkillers， Novex is available from pharmacies without a doctor‘s prescription.
（E） In clinical trials Noxvex has been found more effective than competing brands of painkillers that have been on the market longer than Novex.
18.Hardin argued that grazing land held in common （that is， open to any user） would always be used less carefully than private grazing land. Each rancher would be tempted to overuse common land because the benefits would accrue to the individual， while the costs of reduced land quality that results from overuse would be spread among all users. But a study comparing 217 million acres of common grazing land with 433 million acres of private grazing land showed that the common land was in better condition.
The answer to which of the following questions would be most useful in evaluating the significance， in relation to Hardin‘s claim， of the study described above？
（A） Did any of the ranchers whose land was studied use both common and private land？
（B） Did the ranchers whose land was studied tend to prefer using common land over using private land for grazing？
（C） Was the private land that was studied of comparable quality to the common land before either was used for grazing？
（D） Were the users of the common land that was studied at least as prosperous as the users of the private land？
（E） Were there any owners of herds who used only common land， and no private land， for grazing？
19.Guitar strings often go “dead”-become less responsive and bright in tone-after a few weeks of intense use. A researcher whose son is a classical guitarist hypothesized that dirt and oil， rather than changes in the material properties of the string， were responsible.
Which of the following investigations is most likely to yield significant information that would help to evaluate the researcher‘s hypothesis？
（A） Determining if a metal alloy is used to make the strings used by classical guitarists
（B） Determining whether classical guitarists make their strings go dead faster than do folk guitarists
（C） Determining whether identical lengths of string， of the same gauge， go dead at different rates when strung on various brands of guitars.
（D） Determining whether a dead string and a new string produce different qualities of sound
（E） Determining whether smearing various substances on new guitar string cause them to go dead
key： DEABE ADCE