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
专升本
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
2011-04-26
88
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 (电鱼), of which several kinds live in warm seas. They posses on each side of the head, behind the eyes, a large organ consisting of a number of hexagon- al shaped cells rather like a honeycomb. The cells are filled with a jelly-like substance, and contain a series of flat 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 centimeters 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 (纵向) and are supplied with nerves from the spinal(脊骨)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 (likely) to tire, so they are not able to produce electricity for very long.
The power of producing electricity may serve these fish both for defence and attack.
Usually you will not get a shock by touching the electric ray in one place only because ______. ( )
选项
A、the current in one place is not strong enough to give a shock
B、the fish’s electric cells are filled with jelly-like substance
C、to complete the circuit, you have to touch the fish in two places
D、a torpedo: s electric cells contain more than one electric plates
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/CHqC777K
本试题收录于:
英语题库成考专升本分类
0
英语
成考专升本
相关试题推荐
Manythings______impossibleinthepastarecommontoday.
Johnpromisedtokeephismother______ofhowthingsweregoingonwhenhestudiedinEngland.
Theyhavecooperatedsowellthattheydecideto______theiragreementforanotherfiveyears.
Ishouldhavetoldyou!You______theentirehouse.Ourcleaningladyphonedshe’scomingtomorrow.
Areaswherestudentshaveparticulardifficultyhavebeentreated______particularcare.
Didyouknowthataturtlecanlaytwelveeggsinoneminute?Alargeseaturtlelaysaround150eggsatatime.Shelaysallth
Takethisbaggageand______youcanfindenoughroom.
Lasaisunique______itisthehighestcapitalcityinchina.
AccordingtotheAmericanfederalgovernment,residentsofHawaiihavethelongestlife
TheYellowRiveristhesecond______riverinChina.
随机试题
上道路行驶的机动车故意遮挡、污损、不按规定安装机动车号牌的一次记几分?
A.每搏输出量B.心率C.外周阻力D.主动脉和大动脉弹性
若需拔除位于放射治疗区的患牙,最佳拔牙时间是
判定二尖瓣狭窄的程度,最有价值的检查是
A.变更登记B.缴销C.变相销售D.调剂使用E.SDA批准医疗机构新增配制剂型的,应按规定办理《医疗机构制剂许可证》()
某房地产公司根据市场调查,将目标客户确定为成功的私营企业老板,收入在3000万元以上,选择风景秀丽的都市远郊开发豪华别墅,售价在1000万元以上,其目标市场模式为()。
统计推断是指()。
在()的情况下,月/N比的比值可能较小。
建设工程施工质量验收时,对涉及结构安全和使用功能的重要分部工程,应进行()检测。
Theinterview-about2minutesInthisparttheinterlocutorasksquestionstoeachofthecandidatesinturn.Youhavetogivei
最新回复
(
0
)