中考英语阅读理解专项训练.pdfVIP

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OfalltheanimalsonEarth,nonearemorewillingtoexplorethanhumans.Otheranimals

willgoinsearchoffoodorwater.Buthumansaresearchingforpossibilitiesofdiscovery(发现).

Sowhatcausedustoexploreacrosstheworld?

Maybeit’sinourDNA．In1999,Dr.ChuanshengChencarriedoutastudyofagene(基因)

knownasDRD4-7R.Thisgeneisfoundinabout20%ofallhumans.Thiskindofpeopleare

mostlyinterestedintakingrisk,exploring,andgettingnewideas.Dr.ChenfoundthatDRD4-7R

ismorecommoninpeoplewhomovearoundalotthanthosewhodon’t.Forexample,studiesin

Africashowthatthegeneismuchmorecommoninnomadictribes(游牧的部落)thanintribes

thatliketostayinoneplacebetter.Severalotherresearchershavestudiedthistopicandfoundout

moretosupportDr.Chen’sresearch.

Butcanonegenebeadrive(驱动)fortheneedtoexplore?Dr.Kidddoesn’tthinkso.He

thinksDRD4-7Rmightmakepeoplegetmorecurious(好奇的),butotherimportantsetsgenes

alsogiveusgreatmindsandskilledhands.Hebelievesthatnotjustonegene,butgroupsofgenes

worktogethertocreatebehaviorslikeexploration.

Theenvironmentweliveinalsomakesmuchdifferencetoourneedtoexplore.Forexample,

duringtheEuropeanAgeofExploration,explorersbecamerichandfamousfortheirdiscoveries.

Thismadeotherstrytomakethemselvesbecomerichthroughexplorationtoo.Therefore,their

explorationwasmorelikelyencouragedbymoneythanbygenes.

Maybetheneedtoexplorecomesfromsomethinginsideus,suchastheDRD4-7Rgene.Or

maybeithasmoretodowithwhat’shappeningintheworldaroundus.Maybeit’sboth.Whatever

thereason,itseemswe(oratleastsomeofus)willkeepexploringthemountains,thesea,the

stars,andsoonbecausethat’sjustwhathumansdo.

1WhatdidDr.ChenfindabouttheDRD4-7Rgene?

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A．Itha