The population of peregrine falcons declined rapidly during the 1950’s and 1960’

游客2024-01-13  20

问题 The population of peregrine falcons declined rapidly during the 1950’s and 1960’s and reached an all-time low in the early 1970’s. The decline was attributed by scientists to the widespread use of the pesticide DDT in rural areas. Which of the following, if true, gives the strongest support to the scientists’ claim?

选项 A、DDT was not generally in use in areas devoted to heavy industry.
B、In the time since the use of DDT was banned in 1972, the population of peregrine falcons has been steadily increasing.
C、Peregrine falcons, like other birds of prey, abandon eggs that have fallen out of the nest, even if the eggs remain intact.
D、Starlings, house sparrows, and blue jays-birds the peregrine falcon preys on were not adversely affected by DDT in their habitats.
E、Other birds of prey, such as the osprey, the bald eagle, and the brown pelican, are found in the same areas as is the peregrine falcon.

答案 B

解析 本题由“游隼数量快速下降”这一事实,得出一个解释性的结论“DDT是原因”,属于典型的“B,A”题型的支持,如果自从1972年DDT被禁用以后,游隼数量稳步增加,正如(B)所说,相当于“没有DDT,就没有游隼数量的下降”,即无因就无果。所以(B)是上述推理成立的一个假设,而假设本身就是支持,所以(B)正确。
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