問題詳情

Since the Hawaiian Islands have never been connected to other land masses, the greatvariety of plants in Hawaii must be a result of the long-distance dispersal of seeds, aprocess that requires both a method of transport and an equivalence between the ecology ofthe source area and that of the recipient area.There is some dispute about the method of transport involved. Some biologists arguethat ocean and air currents are responsible for the transport of plant seeds to Hawaii. Yetthe results of flotation experiments and the low temperature of air currents cast doubt onthese hypotheses. More probable is bird transport, either externally, by accidentalattachment of the seeds to feathers, or internally, by the swallowing of fruit and subsequentexcretion of the seeds. While it is likely that fewer varieties of plant seeds have reachedHawaii externally than internally, more varieties are known to be adapted to external than tointernal transport.
46. The author of the passage is primarily concerned with _______.
(A) discussing different theories about the transport of plant seeds toHawaii
(B) discussing the extent to which air currents are responsible for thedispersal of plant seeds to Hawaii
(C) resolving a dispute about the ability of birds to carry plant seedslong distances
(D) resolving a dispute about the adaptability of plant seeds to birdtransport

參考答案

答案：A
難度：適中0.681818
統計：A(45),B(8),C(6),D(7),E(0)

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