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  3. Certainly no creature in the sea is odder than the common sea cucumber. All living creatures, especially human beings, have thei

Certainly no creature in the sea is odder than the common sea cucumber. All living creatures, especially human beings, have thei

admin2012-10-23  74
问题     Certainly no creature in the sea is odder than the common sea cucumber. All living creatures, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous but is considered supremely edible by gourmets?
    For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores.it has the ability to suck up mud or sand and digest whatever nutrients are present
    Sea cucumbers come in a variety of colors, ranging from black to reddish-brown to sand-colored and nearly white. One form even has vivid purple tentacles. Usually the creatures are cucumber-shaped-hence their name and because they are typically rock inhabitants, this shape, combined with their flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents.
    Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate-feeding sparingly or not at all for long periods, so that the marine organisms that provide their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence.
    But the most spectacular thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs. When attacked, it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attacked or even touched: it will do the same if the surrounding water temperature is too high or the water becomes too polluted.
According to the passage, why is the shape of sea cucumber important?
选项 A、Because it helps them digest food
B、Because it helps them protect themselves from danger.
C、Because it makes it easier for them to move through mud.
D、Because it makes them attractive to fish.
答案B
解析 文章指出，海参的外形，以及他们的灵活性，能够让他们钻进裂缝躲避天敌和洋流。第三段thisshape，combined with their flexibility，enables them to squeeze into crevices where they are safefrom predators and ocean currents．
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