Which of the following most logically completes the argument below? When mercury-vapor streetlights are used in areas inhabited

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问题 Which of the following most logically completes the argument below?
When mercury-vapor streetlights are used in areas inhabited by insect-eating bats, the bats feed almost exclusively around the lights, because the lights attract flying insects. In Greenville, the mercury-vapor streetlights are about to be replaced with energy-saving sodium streetlights, which do not attract insects. This change is likely to result in a drop in the population of insect-eating bats in Greenville, since_________.

选项 A、the bats do not begin to hunt until after sundown
B、the bats are unlikely to feed on insects that do not fly
C、the highway department will be able to replace mercury-vapor streetlights with sodium streetlights within a relatively short time and without disrupting the continuity of lighting at the locations of the streetlights
D、in the absence of local concentrations of the flying insects on which bats feed, the bats expend much more energy on hunting for food, requiring much larger quantities of insects to sustain each bat
E、bats use echolocation to catch insects and therefore gain no advantage from the fact that insects flying in the vicinity of streetlights are visible at night

答案D

解析 Argument Construction
Situation In areas with mercury-vapor streetlights, any insect-eating bats feed almost exclusively around the lights, which attract flying insects. In Greenville, mercury-vapor streetlights will soon be replaced with sodium streetlights that do not attract insects.
Reasoning What evidence would suggest that the change in streetlights will reduce Greenville’s population of insect eating bats? Since the sodium streetlights will not attract flying insects, the bats will probably stop focusing their feeding around Greenville’s streetlights after the lights are changed. A statement providing evidence that this will make it harder for the bats to get enough food to sustain themselves would support the conclusion that the change is likely to reduce Greenville’s bat population and thus would logically complete the argument.
A Insect-eating bats existed long before streetlights did, so they can probably find insects away from streetlights even if they hunt only after sundown.
B Greenville will almost certainly still have flying insects for the bats to eat after the change, even if those insects no longer gather around the streetlights.
C If anything, such a smooth transition would be less likely to disturb the bats and therefore less likely to reduce their population.
D Correct. Since there will be no local concentrations of flying insects around Greenville streetlights after the change, the bats will most likely have more trouble getting enough to eat, and that their local population will therefore fall.
E The advantage that the bats gain from mercury-vapor streetlights comes from the high concentration of: insects. The fact that the bats get no additional advantage from the insects’ visibility tells us nothing about what affect the change to a different type of light might have.
The correct answer is D.
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