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  3. Several hundred million years ago, plants similar to modern ferns covered va

Several hundred million years ago, plants similar to modern ferns covered va

游客2025-04-03  23
问题     Several hundred million years ago, plants similar to modern ferns covered vast stretches of the land. Some were as large as trees, with giant fronds bunched at the top of trunks as straight as pillars. Others were the size of bushes and formed thickets of me undergrowth. Still others lived in the shade of giant club mosses and horsetails along the edges of swampy lagoons where giant amphibians swam.
    A great number of these plants were true ferns, reproducing themselves without fruits or seeds. Others had only the appearance of ferns. Their leaves had organs of sexual reproduction and produced seeds. Although their "flowers" did not have corollas these false ferns(today completely extinct)ushered in the era of flowering plants. Traces of these floras of the earliest times have been preserved in the form of fossils. Such traces are most commonly found in shale and sandstone rocks wedged between coal beds.
    Today only tropical forests bear living proof of tile ancient greatness of ferns. The species that grow there are no longer those of the Carboniferous period, but their variety and vast numbers, and the great size of some, remind us of the time when ferns ruled the plant kingdom. [br] Which of the following is NOT mentioned as a characteristic of the plants described in the passage?
选项 A、They once spread over large areas of land.
B、They varied greatly in size.
C、They coexisted with amphibians, mosses, and horsetails.
D、They clung to tree trunks and bushes for support.
答案 D
解析 排除题。选项A在第一段第一、二句话可知它们的体积有很大的，也有很小的；第一段最后一句话证实了C选项(他们与两栖动物、苔、马尾共生)是对的。
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