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
15
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 electric fish produce electricity mainly for ______.
选项
答案
(defence and) attack
解析
由最后一段第一句“The power of producing electricity may serve these fish both for defence and attack”可知答案为defence and attack。
转载请注明原文地址:https://jikaoti.com/ti/mIlMFFFM
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
SituatedattheheartofBeijing,thePalaceMuseumisapproachedthroughtheGateofHeavenlyPeace(Tian’anmen).Becauseofit
SeveralresearchgroupsintheUnitedStatesareconductinggeneticresearchaimedatretardingaging.Ifthebreakthroughsofr
Thetermcultureshockwasintroducedforthefirsttimein1958todescribetheanxietyproducedwhenapersonmovestoacompl
Scientistsareparticularlyinterestedinthebrainsofpeoplewhospeakmorethanonelanguage【C1】flu______becausethatskill
Thepolicemanlookedme______severaltimesandobviouslydislikedwhathesaw.
DevelopingEnvironmentalManagementStrategiesStrongandsustainableeconomicactivitydependsonhealthyenvironmentalman
DevelopingEnvironmentalManagementStrategiesStrongandsustainableeconomicactivitydependsonhealthyenvironmentalman
Waterpollutionisaseriousproblemthreateningthesurvivalofhumanbeings,plantsandanimals.Itisurgentthatsomestrong
HolmesandWatsonhadapprehendedthreepeopleonsuspicionofshoplifting.Thethree,aman,awomanandaboy,wereinterview
CanadianauthoritiesrelayedthatsuspiciontotheU.S.CoastGuard,whichdispatchedacuttertointerceptthevessel.Aftera
随机试题
Weinsistedthathe______badlywoundedandthatadoctor______foratonce.
A、 B、 C、 D、 D
患者,男,56岁,肝硬化。自述乏力、食欲缺乏。体检:神志清楚,消瘦,轻度黄疸,腹部移动性浊音(+)。X线钡餐检查提示胃底食管静脉曲张。护士为患者制定的饮食计划不应包括
包合物的验证方法包括
列为应急保障系统第一位的是信息系统。()
义务教育的强制性是义务教育最本质的特征。()
1941年3月,党的理论工作者张如心首次使用了“毛泽东同志的思想”这一提法。()
一、注意事项1.申论考试是对考生阅读理解能力、综合分析能力、提出和解决问题能力、文字表达能力的综合测试。2.仔细阅读所给材料,按照后面提出的“申论要求”依次作答。二、给定资料1.面对日益严峻的就业形势、新农村建设的急需-双向的渴
在当前打开的表中,显示“地址”以“北京市”打头的所有仓库,正确的命令是()。
有三个关系R、S和T如下:由关系R和S通过运算得到关系T,则所使用的运算为______。
最新回复
(
0
)