Escalating worldwide demand for corn is expected to cause the market price of corn to rise sharply and remain high. Although corn is extensively used as feed for livestock, livestock feed accounts for only a small fraction of the retail price of meat. Therefore, the increase in corn prices is very unlikely to produce any comparable long-term increase in the retail price of meat.

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

Which of the following most logically completes the passage?

Using new detection techniques, researchers have found trace amounts of various medicinal substances in lakes and rivers. Taken in large quantities, these substances could have serious health effects, but they are present in quantities far too low to cause any physiological response in people who drink the water or bathe in it. Nevertheless, medical experts contend that eliminating these trace amounts from the water will have public health benefits, since __________.

Because of steep increases in the average price per box of cereal over the last 10 years, overall sales of cereal have recently begun to drop. In an attempt to improve sales, one major cereal manufacturer reduced the wholesale prices of its cereals by 20 percent. Since most other cereal manufacturers have announced that they will follow suit, it is likely that the level of overall sales of cereal will rise significantly.

Which of the following would it be most useful to establish in evaluating the argument?

Following several years of declining advertising sales, the Greenville Times reorganized its advertising sales force two years ago. Before the reorganization, the sales force was organized geographically, with some sales representatives concentrating on city-center businesses and others concentrating on different outlying regions. The reorganization attempted to increase the sales representatives' knowledge of clients' businesses by having each sales representative deal with only one type of industry or of retailing. After the reorganization, advertising sales increased.

In assessing whether the improvement in advertising sales can properly be attributed to the reorganization, it would be helpful to find out each of the following EXCEPT:

Editor: Articles in Gardening Magazine often spur sales of the plants they describe, particularly among people new to gardening. Accordingly, we will no longer publish articles or accept advertisements praising the beauty of rare wildflowers. Most such plants sold to gardeners have been difficult to propagate under cultivation, so plant sellers often collect them in the wild. Our new policy is part of our efforts to halt this yearly plundering of our native plant populations.

Which of the following, if true, casts the most doubt on the wisdom of the magazine's new policy as a way of pursuing the intended effect?

In a certain wildlife park, park rangers are able to track the movements of many rhinoceroses because those animals wear radio collars. When, as often happens, a collar slips off, it is put back on. Putting a collar on a rhinoceros involves immobilizing the animal by shooting it with a tranquilizer dart. Female rhinoceroses that have been frequently recollared have significantly lower fertility rates than uncollared females. Probably, therefore, some substance in the tranquilizer inhibits fertility.

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

X: In order to reduce the amount of plastic in landfills, legislatures should impose a ban on the use of plastics for packaging goods.

Y: Impossible! Plastic packaging is necessary for public safety. Consumers will lose all of the safety features that plastic offers, chiefly tamper-resistant closures and shatterproof bottles.

Which of the following best describes the weak point in Y's response to X's proposal?

Which of the following most logically completes the argument?

The growing popularity of computer-based activities was widely predicted to result in a corresponding decline in television viewing. Recent studies have found that, in the United States, people who own computers watch, on average, significantly less television than people who do not own computers. In itself, however, this finding does very little to show that computer use tends to reduce television viewing time, since __________.

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?