首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--
The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--
admin
2013-02-03
19
问题
The idea of a fish being able to generate electricity strong enough to light lamp bulbs--or even to run a small electric motor--is almost unbelievable, but several kinds of fish are able to do this. Even more strangely, this curious power has been acquired in different ways by fish belonging to very different families.
Perhaps the best known are the electric rays, or torpedoes, of which several kinds live in warm seas. They possess on each side of the head, behind the eyes, a large organ consisting of a number of hexagonal shaped cells rather like a honeycomb. The cells are filled with a jelly-like substance, and contain a series of fiat electric plates. One side, the negative side, of each plate, is supplied with very fine nerves, connected with a main nerve coming from a special part of the brain. Current passes from the upper, positive side of the organ downwards to the negative, lower side. Generally it is necessary to touch the fish in two places, completing the circuit, in order to receive a shock.
The strength of this shock depends on the size of the fish, but newly born ones only about 5 centimetres across can be made to light the bulb of a pocket flashlight for a few moments, while a fully grown torpedo gives a shock capable of knocking a man down, and, if suitable wires are connected, will operate a small electric motor for several minutes.
Another famous example is the electric eel. This fish gives an even more powerful shock. The system is different from that of the torpedo in that the electric plates run longitudinally and are supplied with nerves from the spinal cord. Consequently, the current passes along the fish from head to tail. The electric organs of these fish are really altered muscles and like all muscles are apt to tire, so they are not able to produce electricity for very long.
The electric catfish of the Nile and of other African fresh waters has a different system again, by which current passes over the whole body from the tail to the head. The shock given by this arrangement is not so strong as the other two, but is none the less unpleasant. The electric catfish is a slow, lazy fish, fond of gloomy places and grows to about 1 metre long; it is eaten by the Arabs in some areas.
The power of producing electricity may serve these fish both for defence and attack. If a large enemy attacks, the shock will drive it away; but it appears that the catfish and the electric eel use their current most often against smaller fish, stunning them so that they can easily be overpowered.
For answers 51-55, mark
Y(for YES) if the statement agrees with the information given in the passage;
N (for NO) if the statement contradicts the information, given in the passage;
NG(for NOT GIVEN) if the information is not given in the passage.
The catfish’s electric current passes from the ______.
选项
答案
tail to the head
解析
由第五段第一句“current passes over the whole body from the tail to the head”可知答案为tail to the head。
转载请注明原文地址:https://kaotiyun.com/show/UWyK777K
本试题收录于:
A类竞赛(研究生)题库大学生英语竞赛(NECCS)分类
0
A类竞赛(研究生)
大学生英语竞赛(NECCS)
相关试题推荐
Notkeenonreading?Doyouhavetroublefindinganovelthatarousesyourinterest?WhynotfollowAmmonShea’sexampleandsta
Somepeoplemaychoosetoliveonwaterforthepleasureandenjoymentofhavingahomethatisdifferentfromthehomesofmost
SituatedattheheartofBeijing,thePalaceMuseumisapproachedthroughtheGateofHeavenlyPeace(Tian’anmen).Becauseofit
SeveralresearchgroupsintheUnitedStatesareconductinggeneticresearchaimedatretardingaging.Ifthebreakthroughsofr
______,computerhasplayedanimportantroleinmodernlife.
TheMid-AutumnFestivalisanimportantfestivalinsomeAsiancountries.Becausethedateofthisfestivalissetaccordingto
Formanypeopletoday,readingisnolongerrelaxation.Tokeepuptheirwork,theymustreadletters,reports,tradepublication
Researchshowsthatifwedon’t__________enoughvitaminD,wewilldevelophealthproblems.
CanadianauthoritiesrelayedthatsuspiciontotheU.S.CoastGuard,whichdispatchedacuttertointerceptthevessel.Aftera
A、Itbringshigherpayandhousingconditions.B、Itsavesalotofjourneytime.C、Itissaferthantravellingbyfoot.D、Itred
随机试题
牙体缺损最常见的原因是
A.必须执行检查制度B.必须准确无误,并正确说明用法、用量和注意事项C.必须有真实完整的购销记录D.必须执行药品保管制度E.必须根据医生处方药品的入库和出库
按《建筑设计防火规范》(GB50016-2014,2008年版)对防火墙的要求,以下错误的是()。
根据《会计法》的规定,下列选项中,属于会计人员职权的有()。
一般说来,金融工程的概念有狭义和广义两种。广义的金融工程是指()。
简述影响态度与品德学习的内部条件。
短跑摆腿动作的作用和要求是什么?
请从所给的选项中,选择最合适的一个,使之呈现一定的规律性:
在此一年一度的广州国际车展即将到来之际,各地经销商________,为在这次空前盛会中________更多眼球做最后准备。填入划横线部分最恰当的一项是()。
有如下程序:#includeusingnamespacestd;classMyClass{public:MyClass(){cout
最新回复
(
0
)