The number of applications for teaching positions in Newtown's public schools was 5.7 percent lower in 1993 than in 1985 and 5.9 percent lower in 1994 than in 1985. Despite a steadily growing student population and an increasing number of teacher resignations, however, Newtown does not face a teacher shortage in the late 1990's.

Which of the following, if true, would contribute most to an explanation of the apparent discrepancy above?

Wolves generally avoid human settlements. For this reason, domestic sheep, though essentially easy prey for wolves, are not usually attacked by them. In Hylantia prior to 1910, farmers nevertheless lost considerable numbers of sheep to wolves each year. Attributing this to the large number of wolves, in 1910 the government began offering rewards to hunters for killing wolves. From 1910 to 1915, large numbers of wolves were killed. Yet wolf attacks on sheep increased significantly.

Which of the following, if true, most helps to explain the increase in wolf attacks on sheep?

Junior biomedical researchers have long assumed that their hirings and promotions depend significantly on the amount of their published work. People responsible for making hiring and promotion decisions in the biomedical research field, however, are influenced much more by the overall impact that a candidate's scientific publications have on his or her field than by the number of those publications.

The information above, if accurate, argues most strongly against which of the following claims?

Every fall Croton's jays migrate south. The jays always join flocks of migrating crookbeaks with which they share the same summer and winter territories. If a jay becomes separated from the crookbeaks it is accompanying, it wanders until it comes across another flock of crookbeaks. Clearly, therefore, Croton's jays lack the navigational ability to find their way south on their own.

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

The general availability of high-quality electronic scanners and color printers for computers has made the counterfeiting of checks much easier. In order to deter such counterfeiting, several banks plan to issue to their corporate customers checks that contain dots too small to be accurately duplicated by any electronic scanner currently available; when such checks are scanned and printed, the dots seem to blend together in such a way that the word "VOID" appears on the check.

A questionable assumption of the plan is that

Many people suffer an allergic reaction to sulfites, including those that are commonly added to wine as preservatives. However, since there are several winemakers producing wine to which no sulfites are added, those who would like to drink wine but are allergic to sulfites can drink these wines without risking an allergic reaction to sulfites.

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

Technological improvements and reduced equipment costs have made converting solar energy directly into electricity far more cost-efficient in the last decade. However, the threshold of economic viability for solar power (that is, the price per barrel to which oil would have to rise in order for new solar power plants to be more economical than new oil-fired power plants) is unchanged at thirty-five dollars.

Which of the following, if true, does most to help explain why the increased cost-efficiency of solar power has not decreased its threshold of economic viability?

In Arumville, among those young children with elevated levels of lead in their blood, few live in houses containing lead-based paint, but many live in areas where vehicular traffic is heavy. These children's elevated blood-lead levels probably result from lead added to gasoline, since, although gasoline sold in and around Arumville has been lead-free since 1990, lead from vehicle exhaust remains in the soil for many years.

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

Given that employees of the XYZ Company could, in theory, do their work at home, the company developed a radical plan to increase efficiency: eliminate office-space expenditures by having employees work at home. To evaluate this plan, XYZ's managers asked volunteers from the company's staff to try the arrangement for six months. There were several volunteers; significantly, their productivity during this period was as high as or higher than before.

Which of the following, if true, would argue most strongly against deciding, on the basis of the trial results, to implement the company's plan?

The country of Baurisia has, until now, been self-sufficient in both grain and meat. However, with growing prosperity in Baurisia has come a steadily increasing per capita consumption of meat, and it takes several pounds of grain to produce one pound of meat. Therefore, since per capita income in Baurisia is almost certain to rise further but increases in domestic grain production are highly unlikely, Baurisia is soon likely to become an importer of grain.

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