托福阅读原文和翻译.doc托福阅读原文及翻译托福阅读原文:ponentsofcells・urringchemicalelements,althoughjust4oftheseelements—oxygen,carbon,hydrogen,andnitrogen—anisms・Thus,,(andatraceamountoflithium)dbystars・auscthcyarchcavierthanhydrogenandhelium・paredtohydrogenandhelium,theyarefoundjustabouteverywhere・Heavyelementsarecontinuallybeingmanufacturedbystarsandreleasedintospacebystellardeaths,paredtohydrogenandheliumgraduallyriseswithtime・Heavyelementsmakeupabout2percentofthechemicalcontent(bymass)ofoursolarsystem,,whichformedbeforemanyheavyelementswereproduced,theheavy-,everystarsystemstudiedhasat1eastsomeamountofal1theelementsusedbylife・Moreover,esimals—small,s一condensewithinaformingstarsystem,theyareinevitab!,esimalseverywhereshouldcontaintheelementsneededforlife,whichmeansthatobjectsbu^esimals—s,moons,asteroids,ets-alsocontaintheseelements・ThenatureofsolarsystemformationexplainswhyEarthcontainsalltheelementsneededforiife,anditiswhyweexpecttheseelementstobepresentonotherworldsthroughoutoursolarsystem,galaxy,anduniverse・tdocsnotchange,ifwcallowforlifcvcrydifferentfromlifeonEarth・LifeonEarthiscarb
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