1. Roses always provide a stunning display of color, but only those flowers that smell sweet are worth growing in a garden. Some roses have no scent. Which one the following conclusions can be properly drawn from the passage?

2. The use of money causes a civilization to decline. That this is true is shown by the way the troubles of Western civilization began with the invention of money. While real money (gold and silver) is bad enough, imitation money (paper money) is a horror. The decline of Western civilization exactly parallels the increasing use of money—both real money and worthless paper money—as a substitute for things of intrinsic value. Which one of the following, if true, could contribute most to a refutation of the argument?

3. Fire ants from Brazil now infest the southern United States. Unlike queen fire ants in Brazil, two queens in the United States share a nest. Ants from these nests are more aggressive than those from single-queen nests. By destroying virtually all insects in the nest area, these aggressive ants gain sole access to food sources, and the ant population skyrockets. Since certain predator insects in Brazil limit the fire-ant population there, importing such predator insects into the United States would be of overall benefit to the environment by stopping the increase of the fire-ant population in the United States. Each of the following is an assumption made in the argument EXCEPT:

4. In an attempt to counter complaints that a certain pesticide is potentially hazardous to humans if absorbed into edible plants, the pesticide manufacturer has advertised that “ounce for ounce, the active ingredient in this pesticide is less toxic than the active ingredient in mouthwash.” Which one of the following, if true, indicates a weakness in the manufacturer’s argument?

5. Four randomly chosen market research companies each produced population estimates for three middle-sized cities; the estimates of each company were then compared with those of the other companies. Two of the cities had relatively stable populations, and for them estimates of current population and of projected population in five years varied little from company to company. However, for the third city, which was growing rapidly, estimates varied greatly from company to company. The passage provides the most support for which one of the following?

6. Four randomly chosen market research companies each produced population estimates for three middle-sized cities; the estimates of each company were then compared with those of the other companies. Two of the cities had relatively stable populations, and for them estimates of current population and of projected population in five years varied little from company to company. However, for the third city, which was growing rapidly, estimates varied greatly from company to company. Which one of the following, if true, would best help explain why estimates of the current population of the rapidly growing city varied more than did current population estimates for the two other cities?

7. Head injury is the most serious type of injury sustained in motorcycle accidents. The average cost to taxpayers for medical care for nonhelmeted motorcycle-accident victims is twice that for their helmeted counterparts. Jurisdictions that have enacted motorcycle-helmet laws have reduced the incidence and severity of accident-related head injuries, thereby reducing the cost to taxpayers. Therefore, to achieve similar cost reductions, other jurisdictions should enact motorcycle-helmet laws. For the same reason jurisdictions should also require helmets for horseback riders, since horseback-riding accidents are even more likely to cause serious head injury than motorcycle accidents are. Which one of the following is an assumption upon which the author’s conclusion concerning helmets for horseback riders depends?

8. The senator has long held to the general principle that no true work of art is obscene, and thus that there is no conflict between the need to encourage free artistic expression and the need to protect the sensibilities of the public from obscenity. When well-known works generally viewed as obscene are cited as possible counterexamples, the senator justifies accepting the principle by saying that if these works really are obscene then they cannot be works of art. The senator’s reasoning contains which one of the following errors?

9. Until he was dismissed amid great controversy, Hastings was considered one of the greatest intelligence agents of all time. It is clear that if his dismissal was justified, then Hastings was either incompetent or else disloyal. Soon after the dismissal, however, it was shown that he had never been incompetent. Thus, one is forced to conclude that Hastings must have been disloyal. Which one of the following states an assumption upon which the argument depends?

10. Anyone who fails to answer a patient’s questions cannot be a competent physician. That is why I feel confident about my physician’s competence: she carefully answers every one of my questions, no matter how trivial. Which one of the following most closely parallels the flawed reasoning in the argument above?

11. The annual Journal for Publication, which often solicits articles, publishes only those articles that are both submitted before March 6 and written by certified psychoanalysts. Stevens, who publishes frequently in psychoanalytic literature, submitted an article to the Journal before March 6. This article was accepted for publication in the Journal. Which one of the following conclusions follows logically from the statements above?

12. Arguing that there was no trade between Europe and East Asia in the early Middle Ages because there are no written records of such trade is like arguing that the yeti, an apelike creature supposedly existing in the Himalayas, does not exist because there have been no scientifically confirmed sightings. A verifiable sighting of the yeti would prove that the creature does exist, but the absence of sightings cannot prove that it does not. Which one of the following best expresses the point of the argument?

13. Arguing that there was no trade between Europe and East Asia in the early Middle Ages because there are no written records of such trade is like arguing that the yeti, an apelike creature supposedly existing in the Himalayas, does not exist because there have been no scientifically confirmed sightings. A verifiable sighting of the yeti would prove that the creature does exist, but the absence of sightings cannot prove that it does not. Which one of the following considerations, if true, best counters the argument?

14. When the economy is in a recession, overall demand for goods and services is low. If overall demand for goods and services is low, bank interest rates are also low. Therefore, if bank interest rates are not low, the economy is not in a recession. The reasoning in which one of the following most closely parallels the reasoning in the argument above?

15. Twenty years ago the Republic of Rosinia produced nearly 100 million tons of potatoes, but last year the harvest barely reached 60 million tons. Agricultural researchers, who have failed to develop new higher-yielding strains of potatoes, are to blame for this decrease, since they have been concerned only with their own research and not with the needs of Rosinia. Which one of the following is an assumption on which the argument depends?

16. An ancient Pavonian text describes how an army of one million enemies of Pavonia stopped to drink at a certain lake and drank the lake dry. Recently, archaeologists discovered that water-based life was suddenly absent just after the event was alleged by the text to have occurred. On the basis of reading the text and an account of the archaeological evidence, some students concluded that the events described really took place. Which one of the following is a questionable technique used by the students to reach their conclusion?

17. Samples from the floor of a rock shelter in Pennsylvania were dated by analyzing the carbon they contained. The dates assigned to samples associated with human activities formed a consistent series, beginning with the present and going back in time, a series that was correlated with the depth from which the samples came. The oldest and deepest sample was dated at 19,650 years before the present, plus or minus 2,400 years. Skeptics, viewing that date as to early and inconsistent with the accepted date of human migration into North America, suggested that the samples could have been contaminated by dissolved “old carbon” carried by percolating groundwater from nearby coal deposits. Which of the following considerations, if true, argues most strongly against the suggestion of the skeptics?

18. Those influenced by modern Western science take it for granted that a genuine belief in astrology is proof of a credulous and unscientific mind. Yet, in the past, people of indisputable intellectual and scientific brilliance accepted astrology as a fact. Therefore, there is no scientific basis for rejecting astrology. The argument is most vulnerable to criticism on which one of the following grounds?

19. Amy McConnell is considering running for election against the incumbent, Gregory Lutz. If Lutz has a large campaign fund, then he is already far ahead, and McConnell will not run against him. If Lutz does not have a large campaign fund, McConnell will scrutinize Lutz’s record for any hints of scandal that she could use against him. Anything of a scandalous nature would increase McConnell’s chances of winning, and she would campaign for election. If Lutz has a clean record, however, McConnell will not run against him. Given the information in the passage, which one of the following must be false?

20. Psychotherapy has been described as a form of moral coercion. However, when people are coerced, their ability to make choices is restricted, and the goal of psychotherapy is to enhance people’s ability to make choices. Hence, psychotherapy cannot possibly be a form of coercion. Which one of the following describes a flaw in the argument?

21. Joel: A myth is a narrative told to convey a community’s traditional wisdom. Myths are not generally told in the modern world because there are no longer bodies of generally accepted truths that can be conveyed in this way. Giselle: Of course there are myths in the modern world. For example, there is the myth of the machine: we see the human body as a machine, to be fixed by mending defective parts. This may not be a narrative, but what medically trained specialist can deny the existence of that myth? Which one of the following most accurately characterizes Giselle’s response to Joel’s statement?

22. The true scientific significance of a group of unusual fossils discovered by the paleontologist Charles Walcott is more likely to be reflected in a recent classification than it was in Walcott’s own classification. Walcott was, after all, a prominent member of the scientific establishment. His classifications are thus unlikely to have done anything but confirm what established science had already taken to be true. Which one of the following most accurately describes a questionable technique used in the argument?

23. Anthony: It has been established that over 80 percent of those who use heroin have a history of having used marijuana. Such evidence would seem to prove that smoking marijuana definitely leads to heroin use. Judith: Maybe smoking marijuana does lead to heroin use, but it is absurd to think that citing those statistics proves that it does. After all, 100 percent of the people who take up heroin had a previous history of drinking water. Judith’s reply to Anthony’s argument relies on which one of the following argumentative strategies?

24. Rumored declines in automobile-industry revenues are exaggerated. It is true that automobile manufacturers’ share of the industry’s revenues fell from 65 percent two years ago to 50 percent today, but over the same period suppliers of automobile parts had their share increase from 15 percent to 20 percent and service companies (for example, distributors, dealers, and repairers) had their share increase from 20 percent to 30 percent. Which one of the following best indicates why the statistics given above provide by themselves no evidence for the conclusion they are intended to support?

25. Proposals for extending the United States school year to bring it more in line with its European and Japanese counterparts are often met with the objection that curtailing the schools’ three-month summer vacation would violate an established United States tradition dating from the nineteenth century. However, this objection misses its mark. True, in the nineteenth century the majority of schools closed for three months every summer, but only because they were in rural areas where successful harvests depended on children’s labor. If any policy could be justified by those appeals to tradition, it would be the policy of determining the length of the school year according to the needs of the economy. Which one of the following principles, if accepted, would provide the strongest justification for the conclusion?

26. Proposals for extending the United States school year to bring it more in line with its European and Japanese counterparts are often met with the objection that curtailing the schools’ three-month summer vacation would violate an established United States tradition dating from the nineteenth century. However, this objection misses its mark. True, in the nineteenth century the majority of schools closed for three months every summer, but only because they were in rural areas where successful harvests depended on children’s labor. If any policy could be justified by those appeals to tradition, it would be the policy of determining the length of the school year according to the needs of the economy. The argument counters the objection by