请阅读Passagel。完成第21—25小题。 Passage1 It'soneofourcommonbeliefsthatmiceareafraidofcats.Scientistshavelongknownthatevenifamousehasneverseenacatbefore,itisstillabletodetectchemicalsignalsreleasedfromitandrunawayinfear.Thishasalwaysbeenthoughttobesomethingthatishard-wiredintoamousesbrain. ButnowWendyIngram,agraduatestudentattheUniversityofCalifornia,Berkeley,haschallengedthiscommonsense.Shehasfoundawayto"cure"miceoftheirinbornfearofcatsbyinfectingthemwithaparasite,reportedthesciencejournalNature. Theparasite,calledToxoplasmagondii,mightsoundunfamiliartoyou,buttheshockingfactisthatuptoone-thirdofpeoplearoundtheworldareinfectedbyit.Thisparasitecancausedifferentdiseasesamonghumans,especiallypregnantwomen--itislinkedtoblindnessandthedeathofunbornbabies. However,theparasite'seffectsonmiceareunique.Ingramandherteammeasuredhowmicereactedtoacat'surine(尿)beforeandafteritwasinfectedbytheparasite.Theynotedthatnormalmicestayedfarawayfromtheurinewhilemicethatwereinfectedwiththeparasitewalkedfreelyaroundthetestarea. Butthat'snotall.Theparasitewasfoundtobemorepowerfulthanoriginallythought—evenafterresearcherscuredthemiceoftheinfection.Theynolongerreactedwithfeartoacat'ssmell,whichcouldindicatethattheinfectionhascausedapermanentchangeinmice'sbrains. Whydoesaparasitechangeamouse'sbraininsteadofmakingitsicklikeitdoestohumans? Theanswerliesinevolution. "It'sexcitingscarytoknowhowaparasitecanmanipulateamouse'sbrainthisway,"Ingramsaid.Butshealsofindsitinspiring."Typicallyifyouhaveabacterialinfection,yougotoadoctorandtakeantibioticsandtheinfectionisclearedandyouexpectallthesymptomstoalsogoaway." Shesaid,butthisstudyhasproventhatwrong."Thismayhavehugeimplicationsforinfectiousdiseasemedicine." Thepassageismainlyabout__________. 查看材料
A.mice' s inborn terror of cats B.the evolution of Toxoplasma C.a new study about the effects of a parasite on mice D.a harmful parasite called Toxoplasma gondii正确答案C
