Which of the following most logically completes the argument?
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants. Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert. Possibly, therefore, the herb's high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants. Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert. Possibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A: histidine is found in all parts of the plant – roots, stem, leaves, and flowers
B: the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids
C: others of the closely related group of plants are also found to produce histidine in large quantities
D: cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic
E: the concentration of histidine in the growing herb declines as the plant approaches maturity
C 很好的一道题目，多体会。
该题目的解释:
植物茂盛与矿物浓度 (详细解释)
A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants. Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert. Possibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.
A: histidine is found in all parts of the plant – roots, stem, leaves, and flowers
B: the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids
C: others of the closely related group of plants are also found to produce histidine in large quantities
D: cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic
E: the concentration of histidine in the growing herb declines as the plant approaches maturity
Networks of blood vessels in bats’ wings serve only to disperse heat generated in flight. This heat is generated only because bats flap their wings. Thus paleontologists’ recent discovery that the winged dinosaur Sandactylus had similar networks of blood vessels in the skin of its wings provides evidence for the hypothesis that Sandactylus flew by flapping its wings, not just by gliding.
Which of the following, if true, most seriously weakens the argument in the passage?
(a)Sandactylus’ wings were far more similar to the wings of bats than to the wings of birds.
(b)Paleontologists do not know whether winged dinosaurs other than Sandactylus had similar networks of blood vessels in the skin of their wings.
(c)The mechanism used by bats for dispersing heat in flight could, in principle, work for much larger flying creatures, such as Sandactylus.
(d)Not all the bats that use the mechanism described in the passage for dispersing heat in flight live in climates similar to the climate in which Sandactylus lived.
(E)Other winged dinosaurs that flew only by gliding had networks of blood vessels in the skin of their wings similar to those that Sandactylus had
答案应该是E，因为blood vessels是flew by flapping its wings的子集，所以gliding的也可能是有blood vessels的。
原题：The city of Workney, in raising bus fares from $1.00 to $1.25, proposed that 18 fare tokens be sold for $20.00 to alleviate the extra burden of the fare increase on the city’s low-income residents. Critics suggested alternatively that 9 fare tokens be sold for $10.00, because a $20.00 outlay would be prohibitive for low-income riders.
The alternative proposal depends on which of the following assumptions?
A. Low-income residents of Workney will continue to ride the buses in the same numbers despite the fare increase.
B. Low-income riders would be more likely to take advantage of the savings afforded by the 9-token offer than would other riders.
C. The outlay of $10.00 for the purchase of 9 fare tokens would not be prohibitive for low-income bus riders.
D. The proposed fare increase is needed for the purchase of new buses for the city’s bus system.
E. Buses provide the only means of public transportation in the city of Workney.
The total market value of real estate in Altonville has steadily declined over the past four years. This decline has meant that the overall figure on which the city’s property tax is based—the assessed value of that real estate—has also declined. The percentage of assessed value that was paid as property taxes to the city, however, did not change from year to year during this period.
The information above most strongly supports which of the following?
The percentage of Altonville’s yearly revenue that comes from money collected in property taxes did not change over the past four years.
The percentage of Altonville’s yearly revenue that comes from money collected in property taxes has declined steadily over the past four years.
The amount of revenue that Altonville collected from property taxes was lower last year than it was four years ago.
During the past four years, Altonville officials increased tax rates on other sources of revenue such as retail sales and business profits.
Altonville will soon require property owners to pay a higher percentage of the assessed value of their property as property tax.
京公网安备11010202008513号 京ICP证101109号 京ICP备12012021号
发表于 2009-1-25 15:21:00
楼主