题目内容：
根据以下材料，回答题It'soneofourcommonbeliefsthatmiceareafraidofcats.Scientistshavelongknownthatevenifamousehasneverseenacatbefore,itisstillabletodetectchemicalsignalsreleasedfromitand
runawayinfear.Thishasalwaysbeenthoughttobesomethingthatishard-wiredintoamouse'sbrain.
ButrecentlyWendyIngrain,agraduatestudentattheUniversityofCalifornia,Berkeley,haschal-lengedthiscommonsense.Shehasfoundawayto"cure"miceoftheirinbornfearofcatsbyinfec-tingthemwithaparasite,reportedthesciencejournalNature.
Theparasite,calledToxoplasmagondii,mightsoundunfamiliartoyou,buttheshockingfactisthatuptoone-thirdofpeoplearoundtheworldareinfectedbyit.Thisparasitecancausedifferentdiseasesamonghumans,especiallypregnantwomen--itislinkedtoblindnessandthedeathofun-bornbabies.
However,theparasite'seffectsonmiceareunique.Ingrainandherteammeasuredhowmicereactedtoacat'surine(尿)beforeandafteritwasinfectedbytheparasite.Theynotedthatnorma
lmicestayedfarawayfromtheurinewhilemicethatwereinfectedwiththeparasitewalkedfreelya-roundthetestarea.
Butthat'snotall.Theparasitewasfoundtobemorepowerfulthanoriginallythought—evenafterresearcherscuredthemiceoftheinfection,theynolongerreactedwithfeartoacat'ssmell,whichcouldindicatethattheinfectionhascausedapermanentchangeinmice'sbrains.
Whydoesaparasitechangeamouse'sbraininsteadofmakingitsicklikeitdoestohumans?
Theanswerliesinevolution.Toxoplasmagondiicanonlyreproduceinsideacat.Sotheparasitehadtodevelopawayoftrickingthemiceintogettingeatenmoreeasily--thushelpingitselfgoinsideacat--bytakingawaymice'ssenseofalarm.
Thepassageismainlyabout__________. A．mice'sinbornterrorofcats
B．theevolutionofToxoplasmagondii
C．anewstory,abouttheeffectsofaparasiteonmice
D．aharmfulparasitecalledToxoplasmagondii
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