年级：九年级
难度：中
图片来源：新闻原文出处
WorldsoldestDNAdiscoveredinmillion-year-oldmammoths
世上最古老的DNA发现于百万年前的猛犸象
ScientistssaytheyhavediscoveredtheoldestDNAonrecord.ItwasfoundintheteethofmammothsthatlivedinnortheasternSiberiaupto1.2millionyearsago.
AmammothwasakindofearlyelephantthatlivedduringtheIceAge.Thediscoverymayleadtoagreaterunderstandingofthelong-deadspecies(物种).
TheresearcherssaytheyrecoveredDNAfromtheremains(残骸)ofthreemammoths.Theremainswerediscoveredinthes.ButscientistsatthetimedidnothavetheabilitytofindandremovetheDNA.
TheoldestofthethreemammothswasdiscoveredneartheKrestovkaRiverinSiberia.Itwasabout1.2millionyearsold.Another,fromneartheAdychaRiver,wasbetween1and1.2millionyearsold.Thethird,fromneartheChukochyaRiver,wasaround,yearsold.
"ThediscoverywasbyfartheoldestDNAeverrecovered,"saidgeneticist(遗传学家)LoveDalénoftheCenterforPalaeogeneticsinSweden.Heledtheresearch,whichwasrecentlydescribedinastudyinthepublicationNature.
However,DNAcanbedamagedovertime.NewresearchmethodsarenowpermittingscientiststorecoverevenolderDNA.Asthesemethodsfurtherdevelop,DalénsaidhethinksitshouldbepossibletoworkwithDNAthatisuptothreemillionyearsold.
Suchmethodscouldleadtoagreaterknowledgeaboutanumberofolderspecies.Theycanprovidevaluableinformationaboutthewaynewspeciesformed,which
fossils(化石)cannot.
1.WheredidthescientistsfindtheoldestDNAonrecord?
A.Intheteethofmammoths.
B.Intheskinofmammoths.
C.Intheeyesofmammoths.
D.Inthelegsofmammoths.
2.WhatcanyouknowaboutLoveDalén?
A.HeisaneditorofNature.
B.Heisateacherinacollege.
C.HeisaresearcherinSiberia.
D.HeisageneticistinSweden.
3.WhichofthefollowingisTRUE?
A.Fossilscanprovidethemostvaluableinformationaboutthespecies.
B.ScientistsmightrecoverDNAthatis2millionyearsoldinthefuture.
C.ScientistsremovedDNAfromtheremainsofthemammothinthes.
（答案见文末）
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答案及解析
1.A
解析：细节理解题。根据文章第一段内容“ScientistssaytheyhavediscoveredtheoldestDNAonrecord.Itwasfoundintheteethofmammoths...”可知科学家们在猛犸象的牙齿中发现了有记录以来最古老的DNA，故选“Intheteethofmammoths.”。
2.D
解析：细节理解题。根据文章第五段内容“...saidgeneticistLoveDalénoftheCenterforPalaeogeneticsinSweden.”可知LoveDalén是瑞典的一名遗传学家，故选“HeisageneticistinSweden.”。
3.B
解析：推理判断题。根据文章第六段内容“Asthesemethodsfurtherdevelop,DalénsaidhethinksitshouldbepossibletoworkwithDNAthatisuptothreemillionyearsold.”可知随着科技的进步，复原高达万年历史的DNA是有可能的，由此可推断出科学家在未来是有可能复原有万年历史的DNA的，故选“ScientistsmightrecoverDNAthatis2millionyearsoldinthefuture.”。
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