精选优质文档-倾情为你奉上托福阅读原文及翻译托福阅读原文：ElementsofLifeThecreationofliferequiresasetofchemicalelementsformakingthecomponentsofcells.LifeonEarthusesabout25ofthe92naturallyoccurringchemicalelements,althoughjust4oftheseelementsoxygen,carbon,hydrogen,andnitrogenmakeupabout96percentofthemassoflivingorganisms.Thus,afirstrequirementforlifemightbethepresenceofmostoralloftheelementsusedbylife.Interestingly,thisrequirementcanprobablybemetbyalmostanyworld.Scientistshavedeterminedthatallchemical
