It’soneofourcommonbeliefsthatmiceareafraidofcats.Scientistshavel

It’soneofourcommonbeliefsthatmiceareafraidofcats.Scientistshavelongknownthatevenifamousehasneverseenacatbefore,itisstillabletodetectchemicalsignalsreleasedfromitandrunawayinfear.Thishasalwaysbeenthoughttobesomethingthatishard-wiredintoamouse’sbrain. 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'sbraininsteadofmakingitsicklikeitdoestohumansTheanswerliesinevolution. “It’sexcitingscarytoknowhowaparasitecanmanipulateamouse'sbrainthisway,"Ingramsaid.Butshealsofindsitinspiring."Typicallyifyouhaveabacterialinfection,yougotoadoctorandtakeantibioticsandtheinfectionisclearedandyouexpectallthesymptomstoalsogoaway,”shesaid,butthisstudyhasproventhatwrong.“Thismayhavehugeimplicationsforinfectiousdiseasemedicine." Theexperimentfoundthatmiceinfectedwithtoxoplasmagondii__________.查看材料

A.stayed far away from cat’s urine

B.moved around the area freely and tearlessly

C.because more sensitive to cat's smell

D.were more afraid of cats

正确答案是B