Less than 35 years after the release of African honeybees outside Sao Paulo, Brazil, their descendants, popularly known as killer bees, had migrated as far north as southern Texas.

Organized in 1966 by the Fish and Wildlife Service, the Breeding Bird Survey uses annual roadside counts along established routes for monitoring of population changes of as many as, or of more than 250 bird species, including 180 songbirds.

To meet the rapidly rising market demand for fish and seafood, suppliers are growing fish twice as fast as their natural growth rate, cutting their feed allotment by nearly half and raising them on special diets.

Certainly, pesticides can adversely affect the environment in localities distant from where the pesticide has actually been used. Nevertheless, regulation of pesticide use should not take place at the national level but at the local level. It is in the areas where pesticides are actually applied that they have their most serious effects. Just how serious these effects are depends on local conditions such as climate, soil type, and water supply. And local officials are much more likely than national legislators to be truly knowledgeable about such local conditions.

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

An overwhelming proportion of the most productive employees at SaleCo's regional work not eight hours a day, five days a week, as do other SaleCo employees, but rather ten hours a day, four days a week, with Friday off. Noting this phenomenon, SaleCo's president plans to increase overall productivity by keeping the offices closed on Fridays and having all employees work the same schedule—ten hours a day, four days a week.

Which of the following, if true, provides the most reason to doubt that the president's plan, if implemented, will achieve its stated purpose?

The Earth's rivers constantly carry dissolved salts into its oceans. Clearly, therefore, by taking the resulting increase in salt levels in the oceans over the past hundred years and then determining how many centuries of such increases it would have taken the oceans to reach current salt levels from a hypothetical initial salt-free state, the maximum age of the Earth's oceans can be accurately estimated.

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

Which of the following most logically completes the argument?

Yorco and Zortech are two corporations that employ large numbers of full-time workers who are paid by the hour. Publicly available records indicate that Yorco employs roughly the same number of such hourly wage workers as Zortech does but spends a far higher total sum per year on wages for such workers. Therefore, hourly wages must be higher, on average, at Yorco than at Zortech, since _____.

Electric utilities pay less for low-quality coal per ton delivered than for high-quality coal. Yet more low-quality coal than high—quality coal must be burned to generate the same amount of electricity. Moreover, per ton of coal burned, low-quality coal generates more ash than does high-quality coal, and the disposal of ash is becoming more and more expensive.

The considerations above, if true, most strongly support which of the following claims?

Frobisher, a sixteenth-century English explorer, had soil samples from Canada's Kodlunarn Island examined for gold content. Because high gold content was reported, Elizabeth I funded two mining expeditions. Neither expedition found any gold there. Modern analysis of the island's soil indicates a very low gold content.Thus the methods used to determine the gold content of Frobisher's samples must have been inaccurate.

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

Southington University's fund-raisers succeeded in getting donations from 80 percent of the potential donors they contacted this year. This rate would be the expected rate if the only potential donors contacted were those who have donated in the past. But good fund-raisers constantly contact less likely prospects in an effort to expand the donor base. Thus the high success rate, far from showing that the fund-raisers did a good job, shows insufficient canvassing effort.

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