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.
中国EMBA的崛起
Tommy’s Essay 汤米的随笔
中国反驳希拉里的非洲讲话
日本首相改组内阁
Lex专栏:铜价反弹
伦敦奥运影响英国国债拍卖
柳州市叫停悬赏捕捞食人鲳行动
英语美文 犹太女孩谱写别样《神曲》
英男子因看奥运面无表情 被警方逮捕
美式运动
建筑师如何打造自己的家
拥有女性董事的中国企业数量大增
微笑与爱心
你真漂亮,她说 Beautiful, She Said
自信
只有发现自己才会享受人生
如再活一次,一切将会不同
希腊有望获得440亿欧元纾困贷款
何谓真爱:爱只是一根线
安南辞任叙利亚特使 联合国大会通过决议谴责叙利亚暴力
人生领悟随感—2
高盛前董事因内幕交易获刑两年
创业吧,享受自由生活!
红丝带
生命即是奇迹 Miraculous
冯建梅事件和解 政府补偿7万余元
我会与你相伴
美总统林肯葛底斯堡演说
培根美文赏析-of travel 论 旅 行
被控在阿富汗屠杀平民的美国士兵周一受审
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |