题目内容：
根据以下材料，回答题Modernscientistsdividetheprocessofdyingintotwostages-clinicalortemporarydeathandbiologicaldeath.Clinicaldeathoccurswhenthevitalorgans,suchastheheartorlungs,haveceasedtofunction,buthavenotsufferedpermanentdamage.The
organismcanstillberevived.Biologicaldeathoccurswhenchangesintheorganismleadtothedisintegrationofvitalceilsandtissues.Deathisthenirreversibleandfinal.
Scientistshavebeenseekingawaytoprolongtheperiodofclinicaldeathsothattheorganismcanberevivedbeforebiologicaldeathoccurs.Thebestmethoddevelopedsofarinvolvescooling
oftheorganism,combinedwithnarcoticsleep.Byslowingdownthebody'smetabolism,coolingde-laystheprocessesleadingtobiologicaldeath.
Toillustratehowthisworks,scientistsperformedanexperimentonasix-year-oldfemalemonkeycalledKeta.ThescientistsputKetatosleepwithanarcotic.Thentheysurroundedherbodywithice-bagsandbegancheckingherbodytemperature.Whenithaddroppedto28degreesthescientistsbegandrainingbloodfromitsbody.Themonkey'sbloodpressuredecreasedandanhourlater
boththeheartandbreathingstopped;clinicaldeathsetin.FortwentyminutesKetare-mainedinthisstate.Hertemperaturedroppedto22degrees.Atthispointthescientistspumped
bloodintoitsbodyinthedirectionoftheheartandstartedartificialbreathing.Aftertwominutesthemonkey'sheartbecameactiveoncemore.Afterfifteenminutes,spontaneousbreathing
began,andafterfourhoursKetaopenedhereyesandliftedherhead.Aftersixhours,whenthescientiststriedtogiveherapenicillininjection,Ketaseizedthesyringeandranwithitaroundthe
room.Herbehaviordifferedlittlefromthatofahealthyanimal.
Thispassagefocuseson A．thedifferencebetweenbiologicalandclinicaldeath
B．theprocessofdying
C．prolongingtheperiodofclinicaldeath
D．thenatureofclinicaldeath
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答案解析：