题目内容：
听音频，回答题 Eachhaironaperson'sheadgrowsfroma26tube-likeholeintheskincalledafollicle(囊).Peoplearebornwithallofthehairfolliclestheyareevergoingtohave.
Thepartofthehairundertheskinisknownasthehairroot.Thehair27outfromtheskinisknownasthehairshaft.Theshaftismadeupofdeadcellsthathavebeen28throughtheroot.Atthebaseofthehairrootisasmallball-like29calledabulb,Thisiswherenewcellsareformed.Thesecellsreceive30fromthebloodsupplyundertheskin.Asnewcellsform,theoldercellsarepushedupthroughtheroot.Intime,theoldcellsarecutofffromthebloodsupplyandbegintoformahardprotein.Thesedeadcellsand31arewhatmakeupthehairshaft.Thiswholeprocessiswhatcauseshairtogrow.
Sowhathappenswhenapersonhastroublegrowinghairor32hairloss?
Yourgenescontrolhowfastorhowlongyourhairwillgrow.Yourhealthcanalsoaffecthairgrowth.Poornutritioncancausesomehairfolliclestostopgrowingorcausethehairsthatgrowtobecomeweakorthin.Somehairlosscanresultfroma33ofgenetics,agingandhormones.Whenthishappens,thehair34changesandthehairfolliclesgetsmaller.Inaddition,thehairsmaygetthinnerandshorter.Soonthehairsstopgrowing35onsomepartsofthehead.
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