1.  The price of maple syrup has jumped front 22 dollars a gallon three years ago to 40 dollars a gallon today. It can be concluded that maple-syrup harvesters have been artificially inflating prices and that governmental price regulations are necessary to control rising prices.
    Which of the following, if true, casts the most doubt on the conclusion drawn above?

• A.The government already requires maple-syrup harvesters to submit their facilities to licensing by the health department.
• B.Insect infestation and drought have stunted the growth of syrup-producing maple trees and caused leas-abundant syrup harvests.
• C.Maple syrup is produced in rural areas that suffer from high unemployment.
• D.Technological improvements in maple-syrup harvesting have reduced production costs.
• E.Maple-syrup prices have risen many times in the past, though never before at the rate recently observed.

2.  The geese that gather at the pond of a large corporation create a hazard for executives who use the corporate helicopter, whose landing site is 40 feet away from the pond. To solve the problem, the corporation plans to import a large number of herding dogs to keep the geese away from the helicopter.
    Which of the following, if a realistic possibility, would cast the most serious doubt on the prospects for success of the corporation's plan?

• A.The dogs will form an uncontrollable pack.
• B.The dogs will require training to learn to herd the geese.
• C.The dogs will frighten away foxes that prey on old and sick geese.
• D.It will be necessary to keep the dogs in quarantine for 30 days after importing them.
• E.Some of the geese will move to the pond of another corporation in order to avoid being herded by the dogs.

3.  Found in caves with the bones of australopithecines, which are thought by some to be ancient ancestors of the human species, were great collections of animal bones. From the frequencies of types of bones, it can be seen that many bones represented only parts of animals that must have died elsewhere. The australopithecines thus must have been mighty hunters, to have brought home so much meat.
    Which of the following, if true, most seriously weakens the conclusion drawn above?

• A.The australopithecines sometimes moved from cave to cave for shelter and did not remain in one cave for a lifetime.
• B.The australopithecine bones found in the caves were those of adult males, adult females, and juveniles.
• C.Evidence of the use of fire was absent from the caves in which the collections of bones were found.
• D.Marks on the bones, including the bones of the australopithecines, are consistent with teeth marks of large catlike animals of the period.
• E.The bones in the cave did not include bones of an elephantlike animal that existed in the area at the time of the australopithecines.

4.  Many researchers believe that the presence of RNA in brain cells is the biochemical basis of memory; that is, the presence of RNA enables us to remember. Because certain chemicals are known to inhibit the synthesis of RNA in the body, we can test this hypothesis. Animals that have learned particular responses can be injected with an RNA inhibitor and then tested for memory of the learned responses. Which of the following test results would most seriously weaken the case for RNA as the basis of memory?

• A.After an injection of RNA inhibitor, a wide range of behaviors in  addition  to  the  learned  responses  were affected.
• B.After an injection of RNA inhibitor, animals that had not consistently been giving the learned responses were able to give them consistently.
• C.After injections of RNA inhibitor, some animals lost memory of the learned responses totally but others lost it only partially.
• D.After a small injection of RNA inhibitor, animals responded well, but as the size of the injection increased, they gave fewer of the learned responses.
• E.After an injection of RNA inhibitor, animals could not learn a new response.

5.  When college students were asked about their experiences in childhood, those who remembered their parents frequently being in pain were also those who experienced common pains, like headaches, most frequently as adults. This evidence argues that a person's childhood observations of adults in pain can make that person more susceptible to pain as an adult.
    Which of the following, if true, most seriously weakens the argument above?

• A.Students who most frequently remembered that they were in pain as children were no more likely than the average student to experience common pains very frequently.
• B.Parents who were frequently in pain when their children were growing up often experience just as much pain after their children have grown up.
• C.College students are in general less susceptible to common pains, like headaches, than are older adults.
• D.Adult memories of the circumstances of childhood pain are often vivid, but adults can rarely recall the subjective experience of being in pain as a child.
• E.A person's adult recollections of childhood are likely to emphasize those memories that reflect the person's adult experiences.

6.  Hotco oil burners, designed to be used in asphalt plants, are so efficient that Hotco will sell one to the Clifton Asphalt plant for no payment other than the cost savings between the total amount the asphalt plant actually paid for oil using its former burner during the last two years and the total amount it will pay for oil using the Hotco burner during the next two years. On installation, the plant will make an estimated payment, which will be adjusted after two years to equal the actual cost savings.
    Which of the following, if it occurred, would constitute a disadvantage for Hotco of the plan described above?

• A.Another manufacturer's introduction to the market of a similarly efficient burner.
• B.The Clifton Asphalt plant's need for more than one new burner.
• C.Very poor efficiency in the Clifton Asphalt plant's old burner.
• D.A decrease in the demand for asphalt.
• E.A steady increase in the price of oil beginning soon after the new burner is installed.

7.  Middletown's police currently remove an apparently abandoned car from the streets about two months after it is reported. The police have been unfairly criticized for allowing such cars to be vandalized during this period. Because it is illegal for car owners to abandon cars on the street, police need not be concerned about protecting such cars.
    Which of the following, if true, most seriously weakens the argument above?

• A.In the past, vehicles abandoned in Middletown were removed from the streets an average of four months after initial reports to police.
• B.In one recent year, more than 150 abandoned vehicles were vandalized in Middletown, but police made no arrests for those actions.
• C.Some cars initially classified by Middletown's police as abandoned were later reclassified as stolen vehicles.
• D.Middletown's understaffed police force must give the disposition of abandoned cars low priority because of the number of violent crimes now committed there.
• E.In the most recent year for which data are available, there were 28 percent fewer reports of abandoned vehicles than the yearly average for the previous ten years.

8.  During his three years in office, the governor of a state has frequently been accused of having sexist attitudes toward women. Yet he has filled five of the nineteen vacant high-level positions in his administration with women appointees, all of whom are still serving. This shows that the governor is not sexist.
    Which of the following statements, if true, would most seriously weaken the conclusion above?

• A.One of the women appointed by the governor to a highlevel position is planning to resign her post.
• B.The platform of the governor's political party required him to appoint at least five women to high-level positions.
• C.Forty-seven percent of the women who voted in the state gubernatorial election three years ago voted for the governor.
• D.A governor of a neighboring state recently appointed seven women to high-level positions.
• E.The governor appointed two Black Americans, two Hispanic Americans, and one Asian American to high-level positions in his administration.

9.  A physician who is too thorough in conducting a medical checkup is likely to subject the patient to the discomfort and expense of unnecessary tests.  One who is not thorough enough is likely to miss some serious problem and therefore give the patient a false sense of security. It is difficult for physicians to judge exactly how thorough they should be. Therefore, it is generally unwise for patients to have medical checkups when they do not feel ill.
    Which one of the following, if true, would most seriously weaken the argument in the passage?

• A.Some serious diseases in their early stages have symptoms that physicians can readily detect, although patients are not aware of any problem.
• B.Under the pressure of reduced reimbursements, pbysicians have been reducing the average amount of time they spend on each medical checkup.
• C.Patients not medically trained are unable to judge for themselves what degree of thoroughness is appropriate for physicians in conducting medical checkups.
• D.Many people are financially unable to afford regular medical checkups.
• E.Some physicians sometimes exercise exactly the right degree of thoroughness in performing a medical checkup.

10.  Researchers studying sets of identical twins who were raised apart in dissimilar environments found that in each case the twins were similar in character, medical history, and life experiences. The researchers saw these results as confirmation of the hypothesis that heredity is more important than environment in determining human personalities and life histories.
    The existence of which of the following would tend to weaken the support for the hypothesis above most seriously?

• A.A set of identical twins raised together who are shown by appropriate tests to have very similar value systems.
• B.A pair or identical twins raised apart who differ markedly with respect to aggressiveness and other personality traits.
• C.A younger brother and older sister raised together who have similar personalities and life experiences.
• D.A mother and daughter who have the same profession even though they have very different temperaments.
• E.A pair of twins raised together who have similar personality traits but different value systems.

11.  The number of people 85 or older in the United States started increasing dramatically during the last ten years. The good health care that these people enjoyed in the United States during their vulnerable childhood years is primarily responsible for this trend.
    Which of the following, if true, most seriously weakens the explanation above?

• A.Seventy-five percent of the people in the United States who are 85 or older are the children of people who themselves lived leas than 65 years.
• B.The people in the United States who are now 85 represent an age group that was smaller in numbers at birth than the immediately preceding and succeeding age groups.
• C.Thirty-five percent of the people in the United States who are 85 or older require some form of twenty-fourhour nursing care.
• D.Many of the people in the United States who are 85 or older immigrated to the United States when they were 20 years old or older.
• E.Because of decreased federal funding for medical care for pregnant mothers and for children, the life expectancy of United States citizens is likely to decrease.

12.  Behind the hope that computers can replace teachers is the idea that the student's understanding of the subject being taught consists in knowing facts and rules, the job of a teacher being to make the facts and rules explicit and convey them to the student, either by practice drills or by coaching. If that were indeed the way the mind works, the teacher could transfer facts and roles to the computer, which would replace the teacher as drillmaster and coach. But since understanding does not consist merely of knowing facts and rules, but of the grasp of the general concepts underlying them, the hope that the computer will eventually replace the teacher is fundamentally misguided.
    Which one of the following, if true, would most seriously undermine the author's conclusion that computers will not eventually be able to replace teachers?

• A.Computers are as good as teachers at drilling students on facts and rules.
• B.The job of a teacher is to make students understand the general concepts underlying specific facts and rules.
• C.It is possible to program computers so that they can teach the understanding of general concepts that underlie specific facts and rules.
• D.Because they are not subject to human error, computers are better than teachers at conveying facts and rules.
• E.It is not possible for students to develop an understanding of the concepts underlying facts and rules through practice drills and coaching.

13.  A certain type of shrimp habitually hovers around superheated deep-sea geysers, near which the bacteria that form the shrimps diet can be found. Because the geysers emit a faint light, scientists have concluded that the shrimps' light sensitive dorsal patches were developed to locate the geysers and thereby find food.
    Which of the following, if true, casts the most doubt on the scientists' conclusion?

• A.The light to which the shrimps are sensitive is not the sort of light that the geysers emit.
• B.The light given off by the geysers too faint to be detected by the human eye.
• C.The heat inside a geyser's stream is sufficient to kill instantly any bacteria that move into it.
• D.Most other types of shrimp use eyes located at the end of eyestalks in order to see.
• E.In other types of shrimp a heat-sensing organ has developed that could serve the same geyser-detecting purposes as the light sensitive patches are said to serve.

14.  Seven countries signed a treaty binding each of them to perform specified actions on a certain fixed date, with the actions of each conditional on simultaneous action taken by the other countries. Each country was also to notify the six other countries when it had completed its action.
    The simultaneous-action provision of the treaty leaves open the possibility that

• A.the compliance date was subject to postponement, according to the terms of the treaty.
• B.one of the countries might not be required to make any changes or take any steps in order to comply with the treaty, whereas all the other countries are so required.
• C.each country might have a well-founded excuse, based on the provision, for its own lack of compliance.
• D.the treaty specified that the signal for one of the countries to initiate action was notification by the other countries that they had completed action.
• E.there was ambiguity with respect to the date after which all actions contemplated in the treaty are to be complete.

15.  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 undermines 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 Novex has been found more effective than competing brands of painkillers that have been on the market longer than Novex.

16.  "This company will not be training any more pilots in the foreseeable future, since we have 400 trained pilots on our waiting list who are seeking employment. The other five major companies each have roughly the same number of trained pilots on their waiting lists, and since the projected requirement of each company is for not many more than 100 additional pilots, there will be no shortage of personnel despite the current upswing in the aviation industry. "
    Which one of the following, if true, casts the most doubt on the accuracy of the above conclusion?

• A.Most of the trained pilots who are on a waiting list for a job are on the waiting lists of all the major companies.
• B.In the long run, pilot training will become necessary to compensate for ordinary attrition.
• C.If no new pilots are trained, there will be an age imbalance in the pilot work force.
• D.The quoted personnel projections take account of the current upswing in the aviation industry.
• E.Some of the other major companies are still training pilots but with no presumption of subsequent employment.

17.  The proposal to hire ten new police officers in Middletown is quite foolish. There is sufficient funding to pay the salaries of the new officers, but not the salaries of additional court and prison employees to process the increased caseload of arrests and convictions that new officers usually generate.
    Which of the following, if true, will most seriously weaken the conclusion drawn above?

• A.Studies have shown that an increase in a city's police force does not necessarily reduce crime.
• B.When one major city increased its police force by 19 percent last year, there were 40 percent more arrests and 13 percent more convictions.
• C.If funding for the new police officers' salaries is approved, support for other city services will have to be reduced during the next fiscal year.
• D.In most United States cities, not all arrests result in convictions, and not all convictions result in prison terms.
• E.Middletown's ratio of police officers to citizens has reached a level at which an increase in the number of officers will have a deterrent effect on crime.

18.  As a promotional experiment, Omega Company distributed four million catalogs. In one of the two versions of the catalog, the description of each item for sate mentioned a "Made by Hand" label. The number of purchases from consumers receiving that catalog was twenty percent greater than the number of purchases from consumers receiving a catalog that did not mention the label. Thus, the mention of the label stimulated sales.
    Which of the following, if true, could best be used to challenge the conclusion drawn above?

• A.Consumers receiving the catalog mentioning the label had previously purchased items from Omega Company by mail but consumers receiving the other catalog had not.
• B.Surveys showed that consumers returned purchased items to Omega Company during the promotional campaign at the same rate regardless of which catalog they received.
• C.The number of purchases from Omega Company declined substantially after the promotional campaign was completed.
• D.Omega Company mailed three times as many catalogs that did not mention the "Made by Hand" label as catalogs that did mention the label.
• E.Omega Company sold twenty percent fewer items during the year of the promotional campaign than it had during the previous year.

19.  Houses built during the last ten years have been found to contain indoor air pollution at levels that are, on average, much higher than the levels found in older houses. The reason air-pollution levels are higher in the newer houses is that many such houses are built near the sites of old waste dumps or where automobile emissions are heavy.
    Which of the following, if true, calls into question the explanation above?

• A.Many new houses are built with air-filtration systems that remove from the house pollutants that are generated indoors.
• B.The easing of standards for smokestack emissions has led to an increase in air-pollution levels in homes.
• C.New houses built in secluded rural areas are relatively free of air pollutants.
• D.Warm-weather conditions tend to slow down the movement of air, thus keeping pollution trapped near its source.
• E.Pressboard, an inexpensive new plywood substitute now often used in the construction of houses, emits the pollutant formaldehyde into the house.

20.  Persons imprisoned for violent street crimes often commit the same crimes again after being released. Persons imprisoned for white-collar crimes such as receiving bribes or embezzlement, however, typically do not, after being released, repeat the crimes for which they have been imprisoned. It is fair to conclude that imprisonment, while it often fails to change the behavior of violent street criminals, does succeed in making white-collar criminals unwilling to repeat their crimes.
    Which of the following, if true, would most seriously weaken the conclusion stated above?

• A.Statistics show that persons convicted of committing white-collar crimes rarely have a prison record.
• B.The percentage of those who commit white-collar crimes and are imprisoned for doing so is lower than the percentage of those who commit violent street crimes and are imprisoned for doing so.
• C.White-collar criminals whose prison sentences are shortened return to criminal activities at a slightly higher rate than white-collar criminals who serve their full sentences.
• D.Persons released from prison after white-collar crimes are seldom given high positions or access to other people's money.
• E.Persons who commit violent street crimes seldom commit white-collar crimes, and vice versa.

21.  In several nineteenth-century paintings the marble buildings of the Acropolis in Athens are portrayed as being reddish, but the buildings do not now appear reddish. The marble's natural color cannot have changed since the nineteenth century, so the paintings must not be showing the color of the buildings as they actually appeared.
    Which of the following, if true, most seriously undermines the argument above?

• A.The Acropolis can be clearly seen from virtually any location within the city of Athens.
• B.Tiny plants called lichens living on marble can cause the marble to appear reddish.
• C.Many nineteenth-century artists strove for tree-to-life accuracy in every detail of their paintings.
• D.Some types of marble are naturally reddish, whereas other types are greenish or white.
• E.Not all nineteenth-century paintings of the Acropolis show the marble buildings as being reddish.

22.  Radioactive radon gas emanating from rock such as granite puts inhabitants of houses built on such rock at greater risk of lung cancer the longer the inhabitants are exposed. Protective steps should be taken if radon measurements exceed 4 picocuries per liter; this recommendation is based on 70 years of occupancy by any one person.
    If a 65-year-old homeowner concludes from the information above that radon testing for the new home she has purchased will not be necessary, then each of the following, if true, weakens the homeowner's argument EXCEPT:

• A.Houses in which the homeowner previously lived were in an area where elevated radon levels have been found.
• B.Houses near the homeowner's new home have radon levels much higher than the 4 picocuries per liter threshold, levels that require immediate action to reduce exposure to any occupants.
• C.The homeowner's granddaughter, who is eventually to inherit the new house, now lives there with her children.
• D.The homeowner smokes cigarettes, and smoking increases the radon-exposure risks over those given in the information.
• E.The strata underlying the homeowner's new home are known to be of rock different from the kinds from which radon emanates.

23.  The large amounts of carbon dioxide now being released into the atmosphere by the burning of fossil fuels will not, in fact, result in a greenhouse effectan increase in average global temperatures. Since plants use carbon dioxide in larger quantities if the supply is increased, they are able to grow larger and multiply more vigorously, and atmospheric carbon dioxide concentrations will eventually become stable.
    Which of the following, if true, would most seriously weaken the conclusion that a greenhouse effect will not result from the current release of large amounts of carbon dioxide into the atmosphere?

• A.The expected rise in average global temperatures has not yet been observed.
• B.Ocean waters absorb carbon dioxide at a greater rate when the atmospheric concentration of carbon dioxide is higher.
• C.Since the beginning of the Industrial Revolution, increased atmospheric concentrations of carbon dioxide have resulted in improved agricultural productivity.
• D.When plants decay, they produce methane, another gas that can have a marked greenhouse effect.
• E.The fact that carbon dioxide levels have risen and fallen many times in the Earth's history suggests that there is some biological process that can reverse the greenhouse effect.

24.  According to a 1980 survey, ten percent of all United States citizens over the age of sixteen are functionally illiterate. Therefore, if the projection that there will be 250 million United States citizens over sixteen in the year 2000 is correct, we project that 25 million of these citizens will be functionally illiterate.
    Which of the following, if true, would most weaken the conclusion drawn by the author of the passage above?

• A.The percentage of high school graduates who do not go on to college has grown steadily over the past two decades.
• B.From 1975 to 1980 there was a three-percent decrease in the rate of functional illiteracy among United States citizens over the age of sixteen.
• C.Many United States citizens included in the 1980 survey would also be included in a survey conducted in the year 2000.
• D.Surveys that are improperly designed usually provide inaccurate results.
• E.In 1980 sixty five percent of all United States citizens were over the age of sixteen.

25.  A greater number of newspapers are sold in Town S than in Town T. Therefore, the citizens of Town S are better informed about major world events than are the citizens of Town T.
    Each of the following, if true, weakens the conclusion above EXCEPT:

• A.Town S has a larger population than Town T.
• B.Most citizens of Town T work in Town S and buy their newspapers there.
• C.The average citizen of Town S spends less time reading newspapers than does the average citizen of Town T.
• D.A weekly newspaper restricted to the coverage of local events is published in Town S.
• E.The average newsstand price of newspapers sold in Town S is lower than the average price of newspapers sold in Town T.

26.  Scientists now believe that artificial-hip implants, previously thought to be safe, may actually increase the risk of cancer in recipients after about 45 years of use. Though these implants do improve the quality of recipients' lives, the increased risk of cancer is an unacceptable price to pay for these improvements. Therefore, they should be banned.
    Which of the following, if true, is the strongest counterargument to the argument above?

• A.Artificial-hip implant surgery can cause severe complications, such as infection, chronic fever, and bone degeneration, and these complications can themselves be crippling or even fatal.
• B.Almost all artificial-hip implant recipients receive their implants at an age when they are unlikely to live more than an additional 30 years.
• C.Although artificial-hip implants increase the risk of cancer after about 45 years of use, a few of the cancers they induce are not fatal.
• D.Since artificial-hip implants are not very common, banning them would cause little hardship.
• E.Although the benefits of artificial-hip implant surgery have remained substantially the same over the past decade, the price of the surgery has risen considerably.

27.  Our words are meaningless and cannot be distinguished from their opposites, as can be proved by an example. People think that they know the difference between the meanings of "bald" and "having hair." Suppose an average person twentyone years of age has N hairs on his or her head. We say that that person is not bald but has hair. But surely one hair less would make no difference, and a person with N-1 hairs on his or her head would be said to have hair. Suppose we kept on, with one hair less each time. The result would be the same. But what would be the difference between someone who had one hair and someone who had none? We call them both bald. Nowhere can we make a distinction between "bald" and "having hair."
    Which of the following statements best counters the argument above?

• A.The word "bald" can be translated into other languages.
• B.A word can have more than one meaning.
• C.A word such as "cat" can be applied to several animals that differ in some respects.
• D.Words can lack precision without being meaningless.
• E.People cannot think clearly without using words.

28.  Tocqueville, a nineteenth-century writer known for his study of democracy in the United States, believed that a government that centralizes power in one individual or institution is dangerous to its citizens. Biographers claim that Tocqueville disliked-centralized government because he blamed Napoleon's rule for the poverty of his childhood in Normandy.
    Which of the following, if true, would cast the most serious doubt on the biographers' claim?

• A.Although Napoleon was popularly blamed at the time for the terrible living conditions in Normandy, historians now know that bad harvests were really to blame for the poor economic conditions.
• B.Napoleon was notorious for refusing to share power with any of his political associates.
• C.Tocqueville said he knew that if his father had not suffered ill health, his family would have had a steady income and a comfortable standard of living.
• D.Although Tocqueville asserted that United States political life was democratic, the United States of the nineteenth century allowed political power to be concentrated in a few institutions.
• E.Tocqueville once wrote in a letter that, although his childhood was terribly impoverished, it was not different from the experience of his friends and neighbors in Normandy.

29.  Nuclear fusion is a process whereby the nuclei of atoms are joined, or "fused," and in which energy is released. One of the by-products of fusion is helium-4 gas. A recent fusion experiment was conducted using "heavy" water contained in a sealed flask. The flask was, in turn, contained in an air-filled chamber designed to eliminate extraneous vibration. After the experiment, a measurable amount of helium-4 gas was found in the air of the chamber. The experimenters cited this evidence in support of their conclusion that fusion had been achieved.
    Which one of the following, if tree, would cast doubt on the experimenters' conclusion?

• A.Helium 4 was not the only gas found in the experiment chamber.
• B.When fusion is achieved, it normally produces several byproducts, including tritium and gamma rays.
• C.The amount of helium 4 found in the chamber's air did not exceed the amount of helium 4 that is found in ordinary air.
• D.Helium 4 gas rapidly breaks down, forming ordinary helium gas after a few hours.
• E.Nuclear fusion reactions are characterized by the release of large amounts of heat.

30.  A steady decline in annual movie-ticket sales is about to begin. More than half of the tickets sold last year were sold to the age group under twenty-five years of age, representing twenty-seven percent of the population. However, the number of individuals under twenty-five will steadily decline during the next decade.
    Which of the following, if true, casts most doubt on the prediction above regarding future movie-ticket sales?

• A.Medical advances have lowered the mortality rates for those who are forty to sixty years of age.
• B.Many people gradually lose interest in going to the movies after they reach twenty-five years of age.
• C.The number of movie theaters has been increasing, and this trend is expected to continue during the next ten years.
• D.Movie-ticket sales tend to increase as the size of the work force increases, and the size of the work force will increase annually during the next decade.
• E.Experts agree that people under twenty-five years of age will continue to account for more than half of the total number of tickets sold in each of the next ten years.

31.  Grazing livestock on public land in the western United States is not causing widespread environmental damage in the region, since if it were, the condition of that land would not be improving. However, only 14 percent of public land in the area today is considered to have inadequate vegetation cover and, therefore, to be in poor condition, while in the 1930's, 36 percent had inadequate vegetation cover.
    Which of the following, if true, most seriously weakens the argument above?

• A.In the western United States, private land is typically more lush than public land, and cattle that graze on private land can be fattened more quickly.
• B.Since the 1930's, recreational users of public land in the western United States have caused more environmental damage than have the cattle grazing there.
• C.During the 1930's, an unusually destructive drought prevailed throughout the region where most public lands in the western United States are located.
• D.Ranchers who use public land in the western United States pay only a fraction of what is paid by those who lease comparable private land for grazing.
• E.The amount of land purchased by the United States government since the 1930's is relatively insignificant.

32.  Extraordinarily few people have the ability to be successful commodity traders. So rather than limit the number of people they hire, trading firms aim to hire all those applicants who are able to be successful and to reject the rest. By this standard Quinsey-Leerheim's record is perfect. All of its entry-level hirees over the past decade have become successful commodity traders.
    Which of the following, if true, would cast the most doubt on the assessment given above of Quinsey-Leerheim's hiring performance?

• A.Over the past decade, Quinsey-Leerheim's trading practices and policies have changed in a way that gives much more responsibility to individual traders.
• B.Since the pool of entry-level applicants is mostly the same for all commodity-trading firms, Quinsey-Leerheim often competes with other trading firms for the strongest applicants.
• C.Quinsey-Leerheim rejects some entry-level applicants who go on to become extremely successful commodity traders with other trading firms.
• D.Commodity trading requires skills that are needed in very few other occupations, so that trading firms' hiring procedures typically differ significantly from those of other financial firms.
• E.Commodity trading is very stressful, and even successful commodity traders rarely work as traders for longer than ten years, although they often earn substantial sums in those years.

33.  Noting that the number of crimes committed in a certain city had decreased in 1982 by 5.2 percent in comparison with 1981, the police chief of the city said, "We see here the result of the innovative police program put into effect in the city at the beginning of 1982."
    Which of the following, if true, most seriously weakens the conclusion drawn by the police chief?

• A.Several cities that have recently increased spending for police programs experienced no decrease in crime in 1982, as compared with 198l.
• B.The number of crimes committed in the city is estimated, by the same method each year, from the number of crimes reported.
• C.The number of crimes committed in the suburban areas surrounding the city rose by about 5 percent in 1982 over the figure for 1981 and were nearly equal in number to those in the city in 1982.
• D.The number of crimes committed in the city in 1982 was 10 percent higher than the number committed in 1972.
• E.The size of the age group most likely to commit crimes decreased considerably in the city in 1982, as against 1981, because of a declining birth rate.

34.  Most disposable plastic containers are now labeled with a code number (from 1 to 9) indicating the type or quality of the plastic. Plastics with the lowest code numbers are the easiest for recycling plants to recycle and are thus the most likely to be recycled after use rather than dumped in landfills. Plastics labeled with the highest numbers are only rarely recycled. Consumers can make a significant long-term reduction in the amount of waste that goes unrecycled, therefore, by refusing to purchase those products packaged in plastic containers labeled with the highest code numbers.
    Which one of the following, if true, most seriously undermines the conclusion above?

• A.The cost of collecting, sorting, and recycling discarded plastics is currently higher than the cost of manufacturing new plastics from virgin materials.
• B.Many consumers are unaware of the codes that are stamped on the plastic containers.
• C.A plastic container almost always has a higher code number after it is recycled than it had before recycling because the recycling process cause a degradation of the quality of the plastic.
• D.Products packaged in plastics with the lowest code numbers are often more expensive than those packaged in the higher-numbered plastics.
• E.Communities that collect all discarded plastic containers for potential recycling later dump in landfills plastics with higher-numbered codes only when it is clear that no recycler will take them.

35.  Until recently experts believed that environment, not genetics, largely determines human personality. A new study, however, has shown that there is more similarity in personality between identical twins raised together than between nonidentical twins raised together. The study concluded that genetics, therefore, does play an important role in determining personality.
    Which of the following, if found to be tree, would cast the most doubt on the study's conclusion?

• A.Identical twins raised separately in different adoptive families are usually more similar in personality than are nonidentical twins raised separately in different adoptive families.
• B.No matter how twins behave, parents treat identical twins in ways that tend to elicit similar personality traits but do not treat nonidentical twins in such ways.
• C.Parents of both identical and nonidentical twins have long claimed that their children, from early infanthood, had definite and well-established personality traits.
• D.Birth parents and their identical twin children tend to become more similar to each other in personality over time, but adoptive parents and their identical twin children do not.
• E.Neither identical nor nonidentical twins are likely to display drastic changes in their individual personalities as they grow up.

36.  The 1988 drought in North America was probably caused by shifts in the temperature patterns of large equatorial stretches of the Pacific Ocean. The drought, therefore, is not evidence for the hypothesis that a long-term global warming trend, allegedly caused by atmospheric pollutants such as carbon dioxide, is occurring.
    Which of the following, if true, constitutes the best criticism of the argument above?

• A.Most pre-1988 droughts for which we have records were preceded by shifts in temperature patterns in the Pacific Ocean.
• B.There has been no warming trend in the United States. over the last 100 years.
• C.The consequences of global warming occur long after the actual emission of pollutants into the atmosphere.
• D.Emissions of carbon dioxide gas into the atmosphere increased in 1988.
• E.A global warming trend could cause increases in the frequency and severity of shifts in temperature patterns in the Pacific Ocean.

37.  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.

38.  John: I have tried several different types of psychotherapy at various times in my life: three kinds of "talk" therapy (Freudian, Rogerian, and cognitive) and also behavior therapy. Since the periods when I was in therapy were the least happy times of my life, I have concluded that psychotherapy cannot work for me.
    Which of the following statements, if true, would most weaken John's conclusion?

• A.Behavior therapy is designed to address different problems from those addressed by "talk" therapies.
• B.The techniques used in behavior therapy are quite different from those used in "talk" therapies.
• C.People who try several different types of psychotherapy tend to be happier than people who try only one type of psychotherapy.
• D.People who try several different types of psychotherapy are more likely to find one that works for them than are people who try only one type of psychotherapy.
• E.People undergoing psychotherapy that ultimately works are often unhappy while they are in therapy.

39.  It was long thought that a now-rare disease of the joints, alkaptonuria, was epidemic in Egypt 2,500 years ago. Evidence came from the high proportion of mummies from that period showing symptoms of the disease. Recently, however, chemical analyses of skeletons have led scientists to propose that the joint damage was actually caused by chemicals used by Egyptian embalmers.
    Which of the following, if true, would additionally weaken the traditional view that alkaptonuria afflicted many Egyptians 2,500 years ago?

• A.X-rays of the mummies showed shadows that clearly suggested joint damage, and recent inspection of the skeletons has confirmed that hypothesis.
• B.Although alkaptonuria is a disease that can be inherited, it did not appear in the descendants of the Egyptian population in which the symptoms were found.
• C.Egyptian embalming methods were highly secret, and scientists are still not certain of the nature of some of the chemicals that were used.
• D.Possible evidence of alkaptonuria has been pointed out in pictures representing the human figure found on artifacts left by other Middle Eastern cultures of that period.
• E.Some mummies of that period show no evidence of joint damage at all.

40.  It is impossible to believe scientific predictions that a long "nuclear winter" would envelop the Earth as a result of nuclear war. Atmospheric scientists and weather experts cannot reliably and accurately predict tomorrow's weather. Yet the effect of nuclear explosions on local and worldwide atmospheric conditions must follow the same laws that control everyday weather changes. If the weather cannot be predicted with present knowledge, neither can a nuclear-winter scenario.
    Which of the following, if true, would most seriously weaken the argument made above that if scientists cannot reliably predict the daily weather, their predictions of a "nuclear winter" cannot be believed?

• A.The scientific theory of a nuclear winter uses data that is available to those who forecast the daily weather.
• B.Scientists' predictions about a nuclear winter are necessarily speculative, since they cannot be verified by harmless experimentation.
• C.Weather forecasters usually do not insist that their predictions are infallible.
• D.Scientific predictions of catastrophic natural events such as volcanic eruptions and earthquakes usually have less reliability than everyday weather predictions.
• E.The scientific theory of a nuclear winter is concerned with drastic climatic changes rather than day-to-day fluctuations in the weather.

41.  In the United States in 1986, the average rate of violent crime in states with strict gun-control laws was 645 crimes per 100,000 persons—about 50 percent higher than the average rate in the eleven states where strict gun-control laws have never been passed. Thus one way to reduce violent crime is to repeal strict gun control laws.
    Which of the following, if true, would most weaken the argument above?

• A.The annual rate of violent crime in states with strict guncontrol laws has decreased since the passage of those laws.
• B.In states with strict gun-control laws, few individuals are prosecuted for violating such laws.
• C.In states without strict gun-control laws, many individuals have had no formal training in the use of firearms.
• D.The annual rate of nonviolent crime is lower in states with strict gun-control laws than in states without such laws.
• E.Less than half of the individuals who reside in states without strict gun-control laws own a gun.

42.  A worldwide ban on the production of certain ozone-destroying chemicals would provide only an illusion of protection. Quantities of such chemicals, already produced, exist as coolants in millions of refrigerators. When they reach the ozone layer in the atmosphere, their action cannot be halted. So there is no way to prevent these chemicals from damaging the ozone layer further.
    Which of the following, if true, most seriously weakens the argument above?

• A.It is impossible to measure with accuracy the quantity of ozone-destroying chemicals that exist as coolants in refrigerators.
• B.In modem societies, refrigeration of food is necessary to prevent unhealthy and potentially life-threatening conditions.
• C.Replacement chemicals that will not destroy ozone have not yet been developed and would be more expensive than the chemicals now used as coolants in refrigerators.
• D.Even if people should give up the use of refrigeration, the coolants already in existing refrigerators are a threat to atmospheric ozone.
• E.The coolants in refrigerators can be fully recovered at the end of the useful life of the refrigerators and reused.

43.  The ratio of divorces to marriages has increased since 1940. Therefore, there must be a greater proportion of children living with only one natural parent than there was in 1940.
    Which of the following, if true, most strongly weakens the inference drawn above?

• A.The number of marriages entered into by women twentyfive to thirty-five years old has decreased since 1940.
• B.When there is a divorce, children are often given the option of deciding which parent they will live with.
• C.Since 1940 the average number of children in a family has remained approximately steady and has not been subject to wide fluctuations.
• D.Before 1940 relatively few children whose parents had both died were adopted into single-parent families.
• E.The proportion of children who must be raised by one parent because the other has died has decreased since 1940 as a result of medical advances.

44.  In the United States, injuries to passengers involved in automobile accidents are typically more severe than in Europe, where laws require a different kind of safety belt. It is clear from this that the United States needs to adopt more stringent standards for safety belt design to protect automobile passengers better.
    Each of the following, if true, weakens the argument above EXCEPT:

• A.Europeans are more likely to wear safety belts than are people in the United States.
• B.Unlike United States drivers, European drivers receive training in how best to react in the event of an accident to minimize injuries to themselves and to their passengers.
• C.Cars built for the European market tend to have more sturdy construction than do cars built for the United States market.
• D.Automobile passengers in the United States have a greater statistical chance of being involved in an accident than do passengers in Europe.
• E.States that have recently begun requiring the European safety belt have experienced no reduction in the average severity of injuries suffered by passengers in automobile accidents.

45.  Grammarians have for years condemned as ungrammatical the English phrase "between you and I," insisting that the correct phrasing is "between you and me," with the objective case after a preposition. Such condemnations, however, are obviously unfounded, because Shakespeare himself, in The Merchant of Venice, wrote, "All debts are cleared between you and I."
    Which of the following, if true, most seriously weakens the argument above?

• A.In his plays, Shakespeare intentionally had some of his characters use phrases he considered ungrammatical.
• B.The phrase "between you and I" appears infrequently in Shakespeare's writings.
• C.The more modern an English word or phrase, the less likely that modem grammarians will consider it acceptable for formal usage.
• D.Many modern speakers of English sometimes say "between you and I" and sometimes say "between you and me."
• E.Most native speakers of English who choose to say "between you and I" do so because they know that Shakespeare used that phrase.

46.  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 productivity, 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 interpretation 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 workroom.
• 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.

47.  Geographers and historians have traditionally held the view that Antarctica was first sighted around 1820, but some sixteenth-century European maps show a body that resembles the polar landmass, even though explorers of the period never saw it. Some scholars, therefore, argue that the continent must have been discovered and mapped by the ancients, whose maps are known to have served as models for the European cartographers.
    Which of the following, if true, is most damaging to the inference drawn by the scholars?

• A.The question of who first sighted Antarctica in modern times is still much debated, and no one has been able to present conclusive evidence.
• B.Between 3,000 and 9,000 years ago, the world was warmer than it is now, and the polar landmass was presumably smaller.
• C.There are only a few sixteenth-century global maps that show a continental landmass at the South Pole.
• D.Most attributions of surprising accomplishments to ancient civilizations or even extraterrestrials are eventually discredited or rejected as preposterous.
• E.Ancient philosophers believed that there had to be a large landmass at the South Pole to balance the northern continents and make the world symmetrical.