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  3. Scientists formerly assumed that coral populations remained stable, dead polyps being replaced by now ones that build on the "sk

Scientists formerly assumed that coral populations remained stable, dead polyps being replaced by now ones that build on the "sk

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问题     Scientists formerly assumed that coral populations remained stable, dead polyps being replaced by now ones that build on the "skeletons" left behind. Recent investigations, however, reveal more dynamic processes. Whole sections of a colony may die and not be replaced. This process, known as partial colony mortality, is evident in a series of photographs over time, but often impossible to detect in site because "skeletons" bared by the death of overlying tissue are readily overgrown by other organisms or abraded by grazers. Partial mortality can produce fission the process of a large colony splitting apart into two or more adjacent colonies that presumably have identical genetic makeup. Subsequent lateral growth may unite these colonies in a process called fusion. As a consequence of these three processes, estimates of coral ages based on size are Partial mortality and fission, which reduce colony size, occur more frequently than fusion, and thus estimates of coral age based on colony size are probably far too low.
Which of the following best describes the organization of the passage?
选项 A、An assumption is stated, processes that undermine that assumption are explained, and an inference is drawn from what has been explained.
B、A scientific problem is examined, reasons why the problem has remained unsolved.
C、Several processes are mentioned, different possible interpretations of those processes are presented and assessed, and a choice of the most satisfactory interpretation is made.
D、Several recently observed natural phenomena are described, their effects on various scientific theories are explained, and the possible consequences of these affects are presented.
答案A
解析 文章结构题。文章开头先指出科学家以往对珊瑚礁的认识，接着指出最近的研究所揭示的以往想象的更复杂的过程，并由此得出结论称通过珊瑚礁的大小来判断它的年龄并非可靠的方法。由此可知A选项(先陈述假设，解释假设的不足，从已有假设中得出推论)最为符合文章结构。
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