【正文】 e city. There has been little parking space, so most buses have idled at the curb during each stop on their tour, and idling produces as much exhaust as driving. The city has now provided parking that acmodates a third of the tour buses, so damage to Palitito39。s buildings from the buses39。 exhaust will diminish significantly. Which of the following, if true, most strongly supports the argument? (A) The exhaust from Palitito39。s few automobiles is not a significant threat to Palitito39。s buildings. (B) Palitito39。s Renaissance buildings are not threatened by pollution other than engine exhaust. (C) Tour buses typically spend less than onequarter of the time they are in Palitito transporting passengers from one site to another. (D) More tourists e to Palitito by tour bus than by any other single means of transportation. (E) Some of the tour buses that are unable to find parking drive around Palitito while their passengers are visiting a site. 21. (28551!item!188。058amp。003690) Traces of cultivated emmer wheat have been found among the earliest agricultural remains of many archaeological sites in Europe and Asia. The only place where the wild form of emmer wheat has been found growing is a relatively narrow strip of southwest Asia. Since the oldest remains of cultivated emmer wheat yet found are from village sites in the same narrow strip, it is clear that emmer wheat was first domesticated somewhere in that strip. Which of the following, if true, most strengthens the argument? (A) The presentday distribution of another wild wheat, einkorn, which was also domesticated early in the development of agriculture, covers a much larger area of southwest Asia. (B) Modern experiments show that wild emmer wheat can easily be domesticated so as to yield nearly as well as traditionally domestic strains. (C) At the time when emmer wheat was first cultivated, it was the most nutritious of all the varieties of grain that were then cultivated. (D) In the region containing the strip where wild emmer wheat has been found, climatic conditions have changed very little since before the development of agriculture. (E) It is very difficult, without geic testing, to differentiate the wild form of emmer wheat from a closely related wild wheat that also grows in southwest Asia. 22. (28829!item!188。058amp。003748) In the late 1980s, the population of sea otters in the North Pacific began to decline. There are two plausible explanations for the decline: predation, possibly by killer whales, or disease. Of these two, disease is the more likely, since a concurrent sharp decline in populations of seals and sea lions is believed to have been caused by disease, and diseases that infect these creatures are likely to be able to infect sea otters also. Which of the following, if true, most seriously weakens the reasoning? (A) Killer whales in the North Pacific usually prey on seals and sea lions but will, when this food source is scarce, seek out other prey. (B) There is no indication that the sea otter population at any North Pacific location declined in the 1980s because of substantial numbers of sea otters migrating to other locations. (C) Along the Pacific coast of North America in the 1980s, sea otters were absent from many locations where they had been relatively mon in former times. (D) Following the decline in the population of the sea otters, there was an increase in the population of sea urchins, which are sea otters39。 main food source. (E) The North Pacific populations of seals and sea lions cover a wider geographic area than does the population of sea otters. 23. (29107!item!188。058amp。003854) From 1978 to 1988, beverage containers accounted for a steadily decreasing percentage of the total weight of household garbage in the United States. The increasingly widespread practice of recycling aluminum and glass was responsible for most of this decline. However, although aluminum recycling was more widely practiced in this period than glass recycling, it was found that the weight of glass bottles in household garbage declined by a greater percentage than the weight of aluminum cans. Which of the following, if true of the United States in the period 1978 to 1988, most helps to account for the finding? (A) Glass bottles are significantly heavier than aluminum cans of parable size. (B) Recycled aluminum cans were almost all beverage containers, but a significant fraction of the recycled glass bottles had contained products other than beverages. (C) Manufacturers replaced many glass bottles, but few aluminum cans, with plastic containers. (D) The total weight of glass bottles purchased by households increased at a slightly faster rate than the total weight of aluminum cans. (E) In many areas, glass bottles had to be sorted by color of the glass before being recycled, whereas aluminum cans required no sorting. 24. (29155!item!188。058amp。003857) Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment39。s rest。 but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop. Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other? (A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping. (B) In pursuing a moving insect, the beetles usually res