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GWD1-Q27 a question about "few weeks"

Here is the whole passage
Recently biologists have been interested in a tide-associated periodic behavior displayed by the diatom Hantzschia virgata, a microscopic golden-brown alga that inhabits that portion of a shoreline washed by tides (the intertidal zone). Diatoms of this species, sometimes called “commuter” diatoms, remain burrowed in the sand during high tide, and emerge on the sand surface during the daytime low tide. Just before the sand is inundated by the rising tide, the diatoms burrow again.  Some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change in pressure caused by tidal movement.  However, when diatoms are observed under constant conditions in a laboratory, they still display periodic behavior, continuing to burrow on schedule for several weeks. This indicates that commuter diatoms, rather than relying on environmental cues to keep time, possess an internal pacemaker or biological clock that enables them to anticipate periodic changes in the environment. A commuter diatom has an unusually accurate biological clock, a consequence of the unrelenting environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.
      This is not to suggest that the period of this biological clock is immutably fixed.  Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors—including changes in the tide’s hydrostatic pressure, salinity, mechanical agitation, and temperature—can alter the period of its biological clock according to changes in the tidal cycle.  In short, the relation between an organism’s biological clock and its environment is similar to that between a wristwatch and its owner:  the owner cannot make the watch run faster or slower, but can reset the hands.  However, this relation is complicated in intertidal dwellers such as commuter diatoms by the fact that these organisms are exposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.

GWD1-Q27:
According to the passage, the periodic behavior displayed by commuter diatoms under constant laboratory conditions is characterized by which of the following?
        
A.    Greater unpredictability than the corresponding behavior under natural conditions
B.    A consistent periodic schedule in the short term
C.    No difference over the long term from the corresponding behavior under natural conditions
D.    Initial variability caused by the constant conditions of the laboratory
E.    Greater sensitivity to environmental factors than is the case under natural conditions


How could we tell if "few weeks" is long or short here for this question regarding choices B & C?

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最后一段开头这句:This is not to suggest that the period of this biological clock is immutably fixed.  Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors—including changes in the tide’s hydrostatic pressure, salinity, mechanical agitation, and temperature—can alter the period of its biological clock according to changes in the tidal cycle。
解释了原因,environmental factors can alter its biological clock,so "over the long term" under natrual conditions 的bioclock和在constant laboratory conditions 下会有不同,B是正确的

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文中之所以要用several weeks加以限制,就是要说明这是一个short term。而且第二段第一句话就说biological clock 并不是永恒不变的,也说明这不是long term

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答案选B,而根据你说的话,应该是C吧。。。

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several weeks就是short term的意思,你想想都用“周”来表示了,还不是短期么,长的要用“年”来
bettyofariN 发表于 2011-6-9 06:28




完全不同意 要是这种生物只能活一个星期 你说a few weeks是长是段呢
a few weeks 不能作为判断标准
判断标准为作者写这段话的目的 some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change in pressure caused by tidal movement.

说这个hypothesize不成立  所以是long-term
只有long-term的表现才能证明一个hypothesize是否成立 short-term的表现会有variation
GMAT不是托福 不考词的意思  考的是作者写作思路 论证方法 逻辑思维和居群语句群之间的关系

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several weeks就是short term的意思,你想想都用“周”来表示了,还不是短期么,长的要用“年”来

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同问。我也选了C,可答案是B.不明白?

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我选的C。发现答案是B。问题会不会出现在C的no difference上,文章说“they still display periodic behavior, continuing to burrow on schedule for several weeks”,没有说和自然条件下的行为完全相同。

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