In the late 1980s, the population of sea otters in the North Pacific Ocean began to decline. Of the two plausible explanations for the decline— increased predation by killer whales or disease—disease is the more likely. After all, a concurrent sharp decline in the populations of seals and sea lions was almost certainly caused by a pollution-related disease, which could have spread to sea otters, whereas the population of killer whales did not change noticeably.Which of the following, if true, most seriously weakens the reasoning?
Kernland imposes a high tariff on the export of unprocessed cashew nuts in order to ensure that the nuts are sold to domestic processing plants. If the tariff were lifted and unprocessed cashews were sold at world market prices, more farmers could profit by growing cashews. However, since all the processing plants are in urban areas, removing the tariff would seriously hamper the government’s effort to reduce urban unemployment over the next five years.Which of the following, if true, most seriously weakens the argument?
In preparation for a large-scale tree-planting project, Thomasville has recorded the location, species, and condition of every tree in its downtown area. The results will be compared with results of the last such tree census, taken 20 years ago. Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now.Which of the following, if true, most seriously undermines the claim that the tree-planting proposal will assure an abundant tree population?
In order to improve the long-term savings rate of its citizens, Levaska’s government has decided to introduce special savings accounts. Citizens can save up to $3,000 a year in special accounts without having to pay tax on the interest, unless they withdraw money from the account before they reach the age of sixty-five. If they do withdraw any money before that age, they have to pay tax on the accumulated interest and a penalty.Which of the following, if true, most seriously threatens the success of the government’s plan?
In the United States, of the people who moved from one state to another when they retired, the percentage who retired to Florida has decreased by three percentage points over the past ten years. Since many local businesses in Florida cater to retirees, this decline is likely to have a noticeably negative economic effect on these businesses.Which of the following, if true, most seriously weakens the argument?
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?
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?