throughout history mAn hAs hAD to ACCEpt thE FACt thAt All living things must DiE, hut pEoplE now livE longEr thAn thEy usED to. yEt, All {{u}} (62) {{/u}} things still show thE EFFECt oF Aging, whiCh will EvEntuAlly {{u}} (63) {{/u}} DEAth. thE BoDy AnD thE {{u}} (64) {{/u}} , thEy Do not FunCtion As wEll As thEy {{u}} (65) {{/u}} in ChilDhooD AnD ADolEsCEnCE(青春期). thE BoDy proviDEs lEss {{u}} (66) {{/u}} AgAinst DisEAsE AnD is morE pronE(易于……的) {{u}} (67) {{/u}} ACCiDEnt. A、numBEr oF rElAtED CAusEs mAy {{u}} (68) {{/u}} to Aging. somE CElls oF thE BoDy hAvE A {{u}} (69) {{/u}} long liFE, But thEy ArE not {{u}} (70) {{/u}} whEn thEy DiE.As A pErson AgEs, {{u}} (71) {{/u}} oF BrAin CElls AnD musClE CElls DECrEAsEs. othEr BoDy CElls DiD AnD ArE rEplACED By nEw CElls. in An Aging pErson thE {{u}} (72) {{/u}} CElls mAy not BE As viABlE(能生存的) or As CApABlE {{u}} (73) {{/u}} growth As thosE oF A young pErson. AnothEr FACtor in Aging mAy BE ChAngEs within thE CElls {{u}} (74) {{/u}} somE oF thE protEin ChEmiCAls in CElls {{u}} (75) {{/u}} known to ChAngE {{u}} (76) {{/u}} AgE AnD BEComE lEss ElAstiC、this is why thE skin oF olD pEoplE wrinklEs AnD hAngs loosE. this is Also thE rEAson olD pEoplE shrink in {{u}} (77) {{/u}}. thErE mAy BE othEr morE importAnt ChEmiCAl ChAngEs in thE CElls. somE ComplEx CEll ChEmiCAls. {{u}} (78) {{/u}}DnA、AnD rnA, storE AnD {{u}} (79) {{/u}} inFormAtion thAt thE CElls nEED、Aging mAy {{u}} (80) {{/u}} this proCEss AnD ChAngE thE inFormAtion CArrying molECulEs {{u}} (81) {{/u}} thEy Do not trAnsmit thE inFormAtion As wEll.

A．prEvEntion
B．protECtion
C．strEngth
D．vitAmin