【RedsquirrelshavebeenwipedoutfromalargeareaofnorthernItaly，threateningafurtherbiodiversitycrisisforthespeciessimilartoitsnearextinctionintheBritishIsles..Therearenownoredsquirrelsleftinanareaofmoreth】

　　RedsquirrelshavebeenwipedoutfromalargeareaofnorthernItaly，threateningafurtherbiodiversitycrisisforthespeciessimilartoitsnearextinctionintheBritishIsles..

　　Therearenownoredsquirrelsleftinanareaofmorethan1，150squarekilometresinPiedmont，accordingtoresearchfromtheuniversitiesofTurinGenoaandVarese.Ontheedgeofthislargeregionthespeciesisalsounderthreatfromtheinvasionsofgreysquirrels.

　　Ifthespreadofthegreysquirrelcontinuesuncontrolled，thespeciescouldspreadasfarasFrance，thescientistsfear.Theyarecallingformoreresearchandcontrolandconservationmeasuresaimedatpreservingtheremainingredsquirrelpopulationsandcontainingthespreadofthegreys.

　　GreysquirrelswereintroducedintoItalyrelativelyrecentlyin1948.TheywereagiftfromtheUSambassadorandkeptinTurin，butescapedintothewildandrapidlycolonizedthesurroundingareadespitewarningsfromtheUK，whereimportinggreysquirrelswasforbiddenfrombeforetheSecondWorldWarwhenthedestructiveeffectsofhavingimportedgreysinthe1880shadbecomeclear.

　　GreysquirrelsarenotonlymoreaggressivethanthenativeEuropeanredsquirrel，whichcauses themtoinvadered-dominatedareasandtakeoverbuttheyalsocarryadeadlyvirusthesquirrelpox.Whilegreysarelargelyimmunetothevirusitisdeadlytoredsquirrelswhichtypicallydiewithinoneortwoweeksofbeinginfected.

　　Fromonlyfouranimalsin1948atStupiniginearTurinthegreysspreadrapidlyinrecentyears.Until1970thedistributionofgreyswaslimitedtotheStupinigiwoodsoccupyinganareaofabout12sqkm.By1990thisareahadexpandedtomorethan200sqkm，stretchingmainlysouthwardsintotheCuneoprovince.

　　By2000，greysquirrelsoccupied900sqkmandthisyear，freshresearchfromthethreeuniversitiesshowsthattheirdistributionnowextendstomorethan2，000sqkm.Inmorethanhalfofthatareathenativeredshavebeenentirelywipedoutandintheremaindertheyareunderseverethreat.

　　( )4.Thebesttitleforthispassageshouldbe

　　A. RedSquirrelsandGreySquirrelsStruggleHard

　　B. RedSquirrelsandGreySquirrelsAreDistributedUnequally

　　C. TheInvasionofFore