Certainly no creature in the sea is odder than the common sea cucumber. All living creature, 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 color 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 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 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 if the water becomes too polluted.
1. According to the passage, why is the shape of sea cucumbers important?
A. It helps them to digest their food.
B. It helps them to protect themselves from danger.
C. It makes it easier for them to move through the mud.
D. It makes them attractive to fish.
2. The fourth paragraph of the passage primarily discusses______.
A. the reproduction of sea cucumbers
B. the food sources of sea cucumbers
C. the eating habits of sea cucumbers
D. threats to sea cucumbers existence
3. What can be inferred about the defence mechanisms of the sea cucumber?
A. They are very sensitive to surrounding stimuli.
B. They are almost useless.
C. They require group cooperation.
D. They are similar to those of most sea creatures.
4. Which of the following would NOT cause a sea cucumber to release its internal organs into the water?
A. A touch B. FoodC. Unusually warm water D. Pollution.
上一篇: 英语专业四级阅读长难句精炼(9)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第22天(含解析)
2017高考英语冲刺讲义:五 动词的时态和语态
2017高考英语冲刺讲义:三 形容词和副词
2017高考英语冲刺讲义:一 名词和主谓一致
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第25天(含解析)
2017高三英语二轮复习 江苏专用 完型填空+阅读理解20
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第11天(含解析)
2017高三英语二轮复习 江苏专用 完型填空+阅读理解15
2017高三英语二轮复习 江苏专用 完型填空+阅读理解14
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第24天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第27天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第20天(含解析)
2017高考英语冲刺讲义:十 状语从句
2017高考英语二轮复习高考倒计时——30天系列课件 高考倒计时6天
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第19天(含解析)
2017高考英语冲刺-动词词组篇 英语短语动词归纳及练习(三)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第28天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第13天(含解析)
2017高考英语冲刺讲义:十三 省略句
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第15天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第23天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第7天(含解析)
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第8天(含解析)
2017高考英语冲刺讲义:六 非谓语动词
2017高三英语二轮复习 江苏专用 完型填空+阅读理解16
2017高考英语冲刺讲义:二 代词
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第14天(含解析)
2017高三英语二轮复习 江苏专用 完型填空+阅读理解19
2017高考英语二轮复习高考倒计时——30天系列练习 高考倒计时第21天(含解析)
2017高三英语二轮复习 江苏专用 完型填空+阅读理解21