A diet high in saturated fats increases a person's risk of developing heart disease. Regular consumption of red wine reduces that risk. Per-capita consumption of saturated fats is currently about the same in France as in the United States, but there is less heart disease there than in the United States because consumption of red wine is higher in France. The difference in regular red-wine consumption has been narrowing, but no similar convergence in heart-disease rates has occurred.

Which of the following, if true, most helps to account for the lack of convergence noted above?

Researchers took a group of teenagers who had never smoked and for one year tracked whether they took up smoking and how their mental health changed. Those who began smoking within a month of the study's start were four times as likely to be depressed at the study's end than those who did not begin smoking. Since nicotine in cigarettes changes brain chemistry, perhaps thereby affecting mood, it is likely that smoking contributes to depression in teenagers.

Which of the following, if true, most strengthens the argument?

Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species. Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates. Clearly, dropping this restriction would allow the other species to recover.

Which of the following, if true, most seriously undermines the argument?

Several of a certain bank's top executives have recently been purchasing shares in their own bank. This activity has occasioned some surprise, since it is widely believed that the bank, carrying a large number of bad loans, is on the brink of collapse. Since the executives are well placed to know their bank's true condition, it might seem that their share purchases show that the danger of collapse is exaggerated. However, the available information about the bank's condition is from reliable and informed sources, and corporate executives do sometimes buy shares in their own company in a calculated attempt to calm worries about their company's condition. On balance, therefore, it is likely that the executives of the bank are following this example.

In the argument given, the two boldfaced portions play which of the following roles?

Certain genetically modified strains of maize produce a natural insecticide that protects against maize-eating insects. The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and often blows onto milkweed plants that grow near maize fields. Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When, in experiments, these caterpillars were fed milkweed leaves dusted with pollen from modified maize plants, they died. Therefore, use of the modified maize inadvertently imperils monarch butterflies.

Which of the following, if true, most seriously weakens the argument?

In general, jobs are harder to get in times of economic recession because many businesses cut back operations. However, any future recessions in Vargonia will probably not reduce the availability of teaching jobs at government-funded schools. This is because Vargonia has just introduced a legal requirement that education in government-funded schools be available, free of charge, to all Vargonian children regardless of the state of the economy, and that current student-teacher ratios not be exceeded.

Which of the following, if true, most strengthens the argument?

Aroca City currently funds its public schools through taxes on property. In place of this system, the city plans to introduce a sales tax of three percent on all retail sales in the city. Critics protest that three percent of current retail sales falls short of the amount raised for schools by property taxes. The critics are correct on this point. Nevertheless, implementing the plan will probably not reduce the money going to Aroca's schools. Several large retailers have selected Aroca City as the site for huge new stores, and these are certain to draw large numbers of shoppers from neighboring municipalities, where sales are taxed at rates of six percent and more. In consequence, retail sales in Aroca City are bound to increase substantially.

In the argument given, the two potions in boldface play which of the following roles?

The milk of many mammals contains cannabinoids, substances that are known to stimulate certain receptors in the brain. To investigate the function of cannabinoids, researchers injected newborn mice with a chemical that is known to block cannabinoids from reaching their receptors in the brain. The injected mice showed far less interest in feeding than normal newborn mice do. Therefore, cannabinoids probably function to stimulate the appetite.

Which of the following is an assumption on which the argument depends?

City Official: At City Hospital, uninsured patients tend to have shorter stays and fewer procedures performed than do insured patients, even though insured patients, on average, have slightly less serious medical problems at the time of admission to the hospital than uninsured patients have. Critics of the hospital have concluded that the uninsured patients are not receiving proper medical care. However,this conclusion is almost certainly false. Careful investigation has recently shown two things: insured patients have much longer stays in the hospital than necessary, and they tend to have more procedures performed than are medically necessary.

In the city official's argument, the two boldface portions play which of the following roles?

A product that represents a clear technological advance over competing products can generally command a high price. Because technological advances tend to be quickly surpassed and companies want to make large profits while they still can, many companies charge the greatest price the market will bear when they have such a product. But large profits on the new product will give competitors a strong incentive to quickly match the new product's capabilities. Consequently, the strategy to maximize overall profit from a new product is to charge less than the greatest possible price.

In the argument above, the two portions in boldface play which of the following roles?