-U6-prehension(SkimmingandScanning)(15minutes)Directions:Inthispart,—7,markY(forYES)ifthestatementagreeswiththeinformationgiveninthepassage;N(forNO)ifthestatementcontradictstheinformationgiveninthepassage;NG(forNOTGIVEN)—,forthefirsttime,,namedDolly,,thetwoareidenticaltwins;’sannouncement,otherscientistsrevealedthattheyhadusedadifferenttechniquetoclonemonkeys,:Shouldscientistsbeallowedtocloneanimals?Iscloningmorallywronganddangerous—orisitavaluableresearchtool?’swhenascientistinDenmarkseparatedcellsfromasheep’sembryo(胚胎).Anembryoisanearlystageofdevelopmentinwhichcellsarebusydividingand“transforming”intospecializedcellslikeskin,eye,,pletelivingthing:—thenanewlygrowingembryo—,,otherscientistshaveusedembryostoclonecattle,pigs,goats,rabbits--and,now,’ssheepunique?Insteadofusingearly-stageembryocells,Wilmutusedcellsfromtheudder(乳腺),that’slikeusingoneofyourskincellstocloneanewyou!icinstructions—pleteindividual.(Theonlyexceptionsareeggandspermcells,eachofwhichcontainshalfthegenestogrowanewindividual.)Oncecellshavespecialized,ingskinoreyeoruddercells,,
李清照诗词全集 来自淘豆网www.taodocs.com转载请标明出处.