题目内容：
根据以下材料，回答题 U.S.toStart$3.2BillionChildHealthStudyinJanuary
Astudythatwillcost$3.2billionandlastmorethantwodecadestotrackthehealthof100,000U.S.childrenfrombeforebirthtoage21willbelaunchedinJanuary,U.S.healthofficialssaidonFriday.
OfficialsfromtheU.S.government'sNationalInstitutesofHealthsaidtheyhopethestudy,tobeconductedat105locationsthroughouttheUnitedStates,canhelpidentifyearly-lifeinfluencesthataffectlaterdevelopment,withthegoaloflearningnewwaystotreatorpreventillness.
Thestudywillexaminehereditaryandenvironmentalfactorssuchasexposuretocertainchemicalsthataffecthealth.
Researcherswillcollectgeneticandbiologicalsamplesfrompeopleinthestudyaswellassamplesfromthehomesofthewomenandtheirbabiesincludingair,water,dustandmaterialsusedtoconstructtheirresidences,theNIHsaid.
Officialssaidmorethan$200millionhasbeenspentalreadyandthestudyisprojectedtocost$3.2billion.
"Weanticipatethatinthelongterm,whatwelearnfromthestudywillresultinasignificantsavingsinthenation'shealthcarecosts,"Dr.DuaneAlexander,whoheadstheNIH'sEuniceKennedyShriverNationalInstituteofChildHealthandHumanDevelopment,toldreporters.
ThestudywillbegininJanuarywhentheUniversityofNorthCarolinaandtheMountSinaiSchoolofMedicineinNewYorkstartsigninguppregnantwomenwhosebabieswillthenbefollowedtoage21.
Someoftheearlyfindingswillbeaboutfactorsbehindpre-termbirth,whichhasbecomemorecommoninrecentyears,accordingtoDr.PeterScheidtoftheNIH,whoheadsthestudy.
Thepeopletakingpartwillbefromrural,urbanandsuburbanareas,fromallincomeandeducationallevelsandfromallracialgroups,theNIHsaid.
Theaimofthestudyistofindnewwaysto__________. A．conductresearch
B．trackpublichealth
C．preventortreatillness
D．speedupdevelopment
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