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TPO软件免费版下载..............................................................................................2LakeWater..............................................................................................................3QuestionsforPassage1..........................................................................................5Passage2:BreathingDuringSleep..........................................................................9QuestionsforPassage2........................................................................................11Passage3.MovingintoPueblos............................................................................15QuestionsforPassage3........................................................................................17

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LakeWater

<1>◆</1>Wheredoesthewaterinalakecomefrom,andhowdoeswaterleaveit?Waterentersalakefrominflowingrivers,fromunderwaterseepsandsprings,fromoverlandflowoffthesurroundingland,andfromrainfallingdirectlyonthelakesurface.Waterleavesalakeviaoutflowingrivers,bysoakingintothebedofthelake,andbyevaporation.[1]Somuch[/1]isobvious.

<2>◆</2><3>◆</3><4>◆</4>Thequestionsbecomemorecomplicatedwhenactualvolumesofwaterareconsidered:howmuchwaterentersandleavesbyeachroute?Discoveringtheinputsandoutputsofriversisamatterofmeasuringthedischargesofeveryinflowingandoutflowingstreamandriver.Thenexchangeswiththeatmospherearecalculatedbyfindingthedifferencebetweenthe[2]gains[/2]fromrain,asmeasured(ratherroughly)byramgauges,andthelossesbyevaporationmeasuredwithmodelsthatcorrectfortheothersourcesofwaterloss.Forthemajorityoflakescertainlythosesurroundedbyforests,inputfromoverlandflowistoosmalltohaveanoticeableeffect.Changesinlakelevelnotexplainedbyriverflowsplusexchangeswiththeatmospheremustbeduetothenetdifferencebetweenwhatseepsintothelakefromthegroundwaterandwhatleaksintothegroundwater.[4]Notetheword"net":[/4]measuringtheactualamountsofgroundwaterseepageintothelakeandoutofthelakeisamuchmorecomplicatedmatterthanmerelyinferringtheirdifference.

<5>◆</5><6>◆</6><13>◆</13>Onceallthisinformationhasbeengathered,itbecomespossibletojudgewhetheralake'sflowismainlyduetoitssurfaceinputsandoutputsortoitsundergroundinputsandoutputs.{13}█{/13}Iftheformeraregreater,thelakeisasurface-water-dominatedlake;ifthelatter,itisaseepage-dominatedlake.{13}█{/13}Occasionally,commonsensetellsyouwhichofthesetwopossibilitiesapplies.{13}█{/13}Forexample,apondinhillycountrythatmaintainsasteadywaterlevelallthroughadrysummerinspiteofhavingnostreamsflowingintoitmustobviouslybeseepagedominated[5].Conversely[/5],apondwithastreamflowinginoneendandouttheother,whichdriesupwhenthestreamdriesup,isclearlysurfacewaterdominated.{13}█{/13}

<7>◆</7>Bywhatevermeans,alakeisconstantlygainingwaterandlosingwater:itswaterdoesnotjustsitthere,or,anyway,notforlong.Thisraisesthematterofalake'sresidencetime.Theresidencetimeistheaveragelengthoftimethatanyparticularmoleculeofwaterremainsinthelake,anditiscalculatedbydividingthevolumeofwaterinthelakebytherateatwhichwater

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leavesthelake.Theresidencetimeisanaverage;thetimespentinthelakebyagivenmolecule(ifwecouldfollowitsfate)woulddependontherouteittook:itmightflowthroughaspartofthefastest,mostdirectcurrent,oritmightcircleinabackwaterforanindefinitelylongtime

<8>◆</8><9>◆</9>Residencetimesvaryenormously.Theyrangefromafewdaysforsmalllal.esuptoseveralhundredyearsforlargeones:LakeTahoe,inCalifornia,hasaresidencetimeof700years.TheresidencetimesfortheGreatLal.esofNorthAmerica,namely,Lal.esSuperior,Michigan.Huron,Erie,andOntario,are,respectively,190,100,22,2.5,http://keErie'sisthelowest:althoughitsareaislargerthanLakeOntario's,itsvolumeislessthanone-thirdasgreatbecauseitissoshallow-lessthan20metersonaverage.

<10>◆</10><11>◆</11><12>◆</12>Agivenlake'sresidencetimeisbynomeansafixedquantity.Itdependsontherateatwhichwaterentersthelake,andthatdependsontherainfallandtheevaporationrate.Climaticchange(theresultofglobalwarming?)isdramaticallyaffectingtheresidencetimesofsomelakesinnorthwesternOntario.Canada.Intheperiod1970to1986,rainfallintheareadecreasedfrom1,000millimetersto650millimetersperannum,whileabove-averagetemperaturesspeededuptheevapotranspirationrate(therateatwhichwaterislosttotheatmospherethroughevaporationandtheprocessesofplantlife).Theresulthasbeenthattheresidencetimeofoneofthela4.esincreasedfrom5to18yearsduringthestudyperiod.Theslowingdownofwaterrenewalleadstoachainof[10]further[/10]consequences:itcausesdissolvedchemicalstobecomeincreasinglyconcentrated,andthis,inturn,hasamarledeffectonalllivingthingsinthelake.

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QuestionsforPassage1

RightAnswer:4

1.Thephrase“Somuch”inthepassagerefersto

thenegativeeffectsofoverlandflow,ram,andevaporationonriverwaterlevels

waterthatalakelosestooutflowingrivers.tothelakebed,andtoevaporation

theimportanceofriverstothemaintenanceoflakewaterlevels

theinformationgivenaboutwaysthatwatercanenterorexitalakeRightAnswer:2

2.Theword"gains"inthepassageisclosestinmeaningto

results

increases

resources

savings

RightAnswer:3

3.Whichofthefollowingcanbeinferredfromparagraph2aboutthemovementofwaterintoalake?

Heavyrainaccountsformostofthewaterthatentersintolakes

Rainfallreplacesapproximatelytheamountofwaterlostthroughevaporation

Overlandflowintolal.esisreducedbythepresenceofforests

Seepagehasasmallereffectonwaterlevelthananyotherinput

RightAnswer:4

4.Whydoestheauthorusethephrase“Notetheword“net””inthepassage?Toemphasizetheimpactofseepageonwaterlevels

Topointoutthatseepageiscalculateddifferentlyfromriverflowsandatmosphericexchanges

Tocomparethedifferentmethodsofcalculatingseepage

Toemphasizethedifficultyofobtainingspecificvaluesforseepageinputs

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andoutputs

RightAnswer:1

5.Theword"Conversely"inthepassageisclosestinmeaningto

ontheotherhand

inthesameway

inotherwords

onaverage

RightAnswer:2

6.Accordingtoparagraph3,whichofthefollowingbestdescribesaseepage-dominatedlake?

Alakethatisfedbystreamsbutstillhasfluctuatingwaterlevels

AlakewithaconstantwaterlevelthathasnostreamsorriversasinputsAlakewithastreamflowingintoitandastreamflowingoutofit

Alakethathassurfaceandundergroundinputsbutloseswaterduringdryseasons

RightAnswer:3

7.Itcanbeinferredfromparagraph4thatthelengthoftimeagivenmoleculeofwaterremainsinalake

dependsentirelyupontheaveragespeedofalake'scurrents

canbemeasuredbythevolumeofthelakealone

canbegreaterorlesserthantheresidencetime

issimilartothelengthoftimeallothermoleculesremaininthatlakeRightAnswer:3

8.Accordingtoparagraph5,LakeErie'sresidencetimeislowerthanLakeOntario'sforwhichofthefollowingreasons?

LakeEriehasalargerareathanLakeOntario.

LakeOntarioisshallowerthanLakeErie.

LakeOntariohasagreatervolumethanLakeErie.

LakeEriereceiveslessrainfallthanLakeOntario.

RightAnswer:1

9.WhydoestheauthordiscusstheGreatLakesinparagraph5?

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TodemonstratetheextenttowhichresidencetimesvaryfromlaketolakeToillustratehowresidencetimesarecalculatedforspecificlakes

Toarguethattheresidencetimeofalakeincreaseswitharea

ToemphasizethatLakeTahoe'sresidencetimeisunusuallylong

RightAnswer:2

10.Theword”further"inthepassageisclosestinmeaningto

expected

additional

serious

unfortunate

RightAnswer:3

11.Accordingtoparagraph6;whichofthefollowingexplainstheincreaseinresidencetimeofsomelakesofnorthwesternOntario?

Theamountofwaterflowingintothelakeshasincreased.

Therateofevaporationhasdecreasedmoresharplythantheamountofrainfall.

Therenewalofthelakes'waterhasslowedduetochangesinclimate.Plantshaverequiredlesswaterfromthelakes

RightAnswer:4

11.Accordingtoparagraph6;whichofthefollowingexplainstheincreaseinresidencetimeofsomelakesofnorthwesternOntario?

Theamountofwaterflowingintothelakeshasincreased.

Therateofevaporationhasdecreasedmoresharplythantheamountofrainfall.

Therenewalofthelakes'waterhasslowedduetochangesinclimate.Plantshaverequiredlesswaterfromthelakes

RightAnswer:413．Lookatthefoursquares[█]thatindicatewherethefollowingsentencecouldbeaddedtothepassage.<i>Ofcourse,alakemaybeneithersurface-water-norseepage-dominatedif,forexample,itsinputsarepredominantlysurfaceanditsoutputsarepredominantlyseepage.</i>Wherewouldthesentencebestfit?Clickonasquaretoaddthesentencetothepassage.█`

█

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█

█

RightAnswer:1,3,4

14．Directions:http://pletethesummarybyselectingtheTHERRanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.Waterenters,remains,andeventuallyleavesalakeinavarietyofways.Clickon3Answers.

Bymeasuringthewaterquantitiesateachofalake'sinputsandoutputs,itcanbedeterminedwhetherwaterenterthelakemainlyfromsurfaceorgroundwatersources

Itissometimespossibletodecidewhetheralakeissurfacewaterdominatedorseepagedominatedbysimpleobservationatdifferentseasons.

Theresidencetimesofsurface-water-dominatedlakesareusuallylongerthanthoseofseepage-dominatedlakes

Changesinlakelevelandvolumearecausedprincipallybytheamountofevaporationofwaterintotheatmosphere

Theaverageperiodoftimethatmoleculesofwaterspendinalake-theresidencetime-variesfromlaketolakeandovertimewithinaparticularlake.

Theresidencetimeofalakefrequentlydependsonthekindsoforganismstobefoundinthelake

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Passage2:BreathingDuringSleep

<1>◆</1>Ofallthephysiologicaldifferencesinhumansleepcomparedwithwakefulnessthathavebeendiscoveredinthelastdecade,changesinrespiratorycontrolaremostdramatic.Notonlyaretheredifferencesinthelevelofthefunctioningofrespiratorysystems,thereareevenchangesinhowtheyfunction.Movementsoftheribcageforbreathingarereducedduringsleep,makingthecontractionsofthediaphragmmoreimportant.{12}█{/12}Yetbecauseofthephysicsoflyingdown,thestomachappliesweightagainstthediaphragmandmakesitmoredifficultforthediaphragmtodoitsjob.{12}█{/12}However,therearemanyotherchangesthataffectrespirationwhenasleep.

<2>◆</2>{12}█{/12}Duringwakefulness,breathingiscontrolledbytwointeractingsystems.{12}█{/12}Thefirstisanautomatic,metabolicsystemwhosecontroliscenteredinthebrainstem.Itsubconsciouslyadjustsbreathingrateanddepthinordertoregulatethelevelsofcarbondioxide(C02,)andoxygen(02,),andtheacid-baseratiointheblood.Thesecondsystemisthevoluntary,behavioralsystem.Itscontrolcenterisbasedintheforebrain,anditregulatesbreathingforuseinspeech,singing,sighing,andsoon.Itiscapableofignoringoroverridingtheautomatic,metabolicsystemandproducesanirregularpatternofbreathing.

<3>◆</3><4>◆</4>DuringNREM(thephaseofsleepinwhichthereisnorapideyemovement)breathingbecomesdeeperandmoreregular,butthereisalsoadecreaseinthebreathingrate,resultinginlessairbeingexchangedoverall.ThisoccursbecauseduringNREMsleeptheautomatic,metabolicsystemhas[3]exclusive[/3]controloverbreathingandthebodyuseslessoxygenandproduceslesscarbondioxide.Also,duringsleeptheautomaticmetabolicsystemislessresponsivetocarbondioxidelevelsandoxygenlevelsintheblood.Twothingsresultfromthesechangesinbreathingcontrolthatoccursduringsleep.First,theremaybeabriefcessationorreductionofbreathingwhenfallingasleepasthesleeperwaxesandwanesbetweensleepandwakefulnessandtheirdifferingcontrolmechanisms.Second,oncesleepisfullyobtained,thereisanincreaseofcarbondioxideandadecreaseofoxygeninthebloodthatpersistsduringNREM.

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<5>◆</5><6>◆</6>Butthatisnotallthatchanges.Duringallphasesofsleep,severalchangesintheairpassageshavebeenobserved.Ittalestwiceasmuchefforttobreatheduringsleepbecauseofgreaterresistancetoairflowintheairwaysandchangesintheefficiencyofthemusclesusedforbreathing.Someofthemusclesthathelpkeeptheupperairwayopenwhenbreathingtendtobecomemorerelaxedduringsleep,especiallyduringREM(thephaseofsleepinwhichthereisrapideyemovement).Withoutthismuscularaction,

[5]inhalingislikesuckingairoutofaballoon[/5]-thenarrowpassagestendtocollapse.Alsothereisaregularcycleofchangeinresistancebetweenthetwosidesofthenose.Ifsomethingblocksthe"good"side,suchascongestionfromallergiesoracold,thenresistanceincreasesdramatically.Coupledwiththesefactorsisthelossofthecomplexinteractionsamongthemusclesthatcanchangetherouteofairflowfromnosetomouth.

<7>◆</7><8>◆</8><9>◆</9><10>◆</10>Otherrespiratoryregulatingmechanismsapparentlyceasefunctioningduringsleep.Forexample,duringwakefulnessthereisanimmediate.Automatic,adaptiveincreaseinbreathingeffortwheninhalingismademoredifficult(suchasbreathingthrougharestrictivefacemask).ThisreflexiveadjustmentistotallyabsentduringNREMsleep.Onlyafterseveralinadequatebreathsundersuchconditions,resultinginthe[9]considerable[/9]elevationofcarbondioxideandreductionofoxygenintheblood,isbreathingeffortadjusted.Finally,thecoughingreflexinreactiontoirritantsintheairwayproducesnotacoughduringsleepbutacessationofbreathing.Iftheirritationissevereenough,asleepingpersonwillarouse,cleartheairway,then[10]resume[/10]breathingandlikelyreturntosleep.

<11>◆</11>AdditionalbreathingchangesoccurduringREMsleepthatareevenmoredramaticthanthechangesthatoccurduringNREM.

[11]TheamountofairexchangedisevenlowerinREMthanNREMbecause,althoughbreathingismorerapidinREM,itisalsomoreirregular,withbriefepisodesofshallowbreathingorabsenceofbreathing.[/11]Inaddition,breathingduringREMdependsmuchmoreontheactionofthediaphragmandmuchlessonribcageaction.

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QuestionsforPassage2

RightAnswer:2

1.Accordingtoparagraph1.whichofthefollowingcanbeinferredaboutthediaphragmduringsleep?

Duringsleepthediaphragmrequiresincreasedmovementoftheribcage.Thediaphragmhelpswithbreathingasmovementsoftheribcagedecreaseduringsleep.

Thediaphragmrequiresagreatamountofpressuretofunctionproperly.ThediaphragmcontributestotheeffectivefunctioningoftheribcageRightAnswer:1

2.Accordingtoparagraph2,allofthefollowingaretrueofthevoluntarybreathingsystemEXCEPT:

Ithasitscontrolcenterinthebrainstem

Itcontrolsbreathingforanumberofactivitiesduringwakefulness.

Itisabletobypasstheautomaticsystem.

Itproducesanirregularbreathingpattern

RightAnswer:4

3.Theword"exclusive"inthepassageisclosestinmeaningto

consistent

perfect

partial

sole

RightAnswer:2

4.Accordingtoparagraph3,whichofthefollowingmayoccurjustbeforeNREMsleepbegins?

Theautomatic,metabolicsystemmayincreaseitsdependenceonairexchanges.

Breathingcanstopforashorttimeasapersonfallsasleep.

Anincreaseintheoxygenlevelinthebloodcanoccurassleepbecomesfullyobtained

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Thelevelofcarbondioxideinthebloodmaydropsuddenly

RightAnswer:35.Whatistheauthor'spurposeinstatingthat0Inhalingislikesuckingairoutofaballoon"?

Torefutetheargumentthatadditionaleffortisnecessaryforbreathingduringsleep

ToarguethatREMsleepismoreimportantthanNREMsleep

Toillustratethedifficultyofbreathingduringsleep

Toillustratehowblockageofnarrowpassagescanbepreventedduringsleep

RightAnswer:3

6.Allofthefollowingarementionedinparagraph4asbeingcharacteristicofbreathingduringsleepEXCEPT

relaxationofthemusclesinvolvedintherespiratorysystem

changesinresistancebetweenthetwosidesofthenose

easierairflowinthepassagesoftheupperairway

absenceofcertaincomplexmuscleinteractions

RightAnswer:2

7.Accordingtoparagraph5;whathappensduringNREMsleepwheninhalingisdifficult?

Thereisanimmediate,automatic,adaptiveincreaseinbreathingeffortThesleepingpersontalesseveralinadequatebreathsbeforethebreathingeffortisadjusted

Thecoughingreflexcausesthebreathingefforttoadjust.

Theairwaysbecomeclearedasthebloodremovesirritants.

RightAnswer:4

8.Itcanbeinferredfromparagraph5thataverymildirritationduringsleepwilllikelycause

thesleepingpersontoincreasethebreathingeffort

wakeupandremovethesourceofirritation

coughwhilestillsleeping

stopbreathingtemporarilywhilestillsleeping

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RightAnswer:1

9.Theword"considerable"inthepassageisclosestinmeaning

significant

steady

usual

necessary

RightAnswer:4

10.Theword"resume"inthepassageisclosestinmeaningto

reduce

stop

readjust

restart

RightAnswer:1

11.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.

BecausebreathingismoreshallowandirregularinREMthaninNREM,lessairisexchangedinREM

BreathinginNREMislesseffectivethanbreathinginREMbecauseofirregularepisodesofrapidbreathingduringNREM.

BecausebreathingismorerapidinNREMsleepthaninREMsleep,breathingoftenbecomesshallow.

AlthoughREMhasbriefepisodesofshallowbreathingorlackofbreathing,breathingismorerapidthaninNRFM

Rightanswers:312.Lookatthefoursquares[█]thatindicatewherethefollowingsentencecouldbeaddedtothepassage.<i>Tobetterunderstandbreathingduringsleep,itis,however,helpfultofirstunderstandhowrespirationworksingeneral.</i>Wherewouldthesentencebestfit?Clickonasquaretoaddthegeneral.

sentencetothepassage.

█

█

█

█

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Rightanswers:246;17

13Directions:Fromthesevenstatementsbelow,selectthestatementsthatcorrectlycharacterisebreathingduringwakefulnessandthosestatementsthatcorrectlycharacterisebreathingduringsleep.TwooftheanswerchoiceswillNOTbeused.Thisquestionisworth3points.

Sleep(3answers)

Wakefulness(2answers)

Theroleoftheribcageincreasesandtheroleofthediaphragmdecreases

Carbondioxideinbloodrisesandoxygendrops

Thecoughingreflexisextremelycomplex

Agreatdealofeffortisusedforbreathing

Upperairwaysareresistanttocoldsandallergies

Thereisadropinthevolumeofairthatisexchanged

Automaticandvoluntaryrespiratorysystemsarebothinvolved

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Passage3.MovingintoPueblos

<14>◆</14><15>◆</15><16>◆</16><17>◆</17><26>◆</26>IntheMesaVerdeareaoftheancientNorthAmericanSouthwest,livingpatternschangedinthethirteenthcentury,withlargenumbersofpeoplemovingintolargecommunaldwellingscalledpueblos,oftenconstructedattheedgesofcanyons,especiallyonthesidesofcliffs.Abandoningsmallextended-familyhouseholdstomoveintotheselargepuebloswithdozensifnothundredsofotherpeoplewasprobably[14]traumatic[/14].Fewoftheculturaltraditionsandrulesthattodayallowustodealwithdensepopulationsexistedforthesepeopleaccustomedtohouseholdautonomyandtheabilitytomovearoundthelandscapealmostatwill.{26}█{/26}Andbesidestheawkwardnessofhavingtosharewallswithneighbors,livinginaggregatedpueblosintroducedotherproblems.{26}█{/26}Forpeopleincliffdwellings,haulingwater,wood,andfoodtotheirhomeswasamajorchore.{26}█{/26}Thestressonlocalresources,especiallyinthefirewoodneededfordailycoolingandwarmth,wasparticularly

[15]intense[/15],andconditionsinaggregatedpuebloswerenotveryhygienic.{26}█{/26}

Givenallthedisadvantagesoflivinginaggregatedtown,whydidpeopleinthethirteenthcenturymoveintothesecloselypackedquarters?Fortransitionsofsuchsuddennessarchaeologistsconsidereitherpullfactors(benefitsthatdrewfamiliestogether)orpushfactors(someexternalthreatorcrisisthatforcedpeopletoaggregate).Inthiscase,pushexplanationsdominate.

<18>◆</18><19>◆</19>Populationgrowthisconsideredaparticularlyinfluentialpush.Afterseveralgenerationsofpopulationgrowth,peoplepackedthelandscapeindensitiessohighthatcommunalpueblosmayhavebeenanecessaryoutcome.AroundSandCanyon,forexample,populationsgrewfrom5-12peoplepersquarekilometerinthetenthcenturytoasmanyas30-50bythe1200s.Asdensitiesincreased,domesticarchitecturebecamelarger,culminatingincrowdedpueblos.[19]Somescholarsexpandonthisideabyemphasizingacorrespondingneedforarablelandtofeedgrowingnumbersofpeople:constructionofsmalldams,reservoirs,terraces,andfieldhousesindicatesthatfarmerswereintensifyingtheireffortsduringthe1200s.[/19]Competitionforgoodfarmlandmayalsohavepromptedpeopletobondtogethertoassertrightsoverthebestfields.

<20>◆</20><21>◆</21><22>◆</22>AnotherimportantpushwastheonsetoftheLittleIceAge,aclimaticphenomenonthatledtocooler

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temperaturesintheNorthernHemisphere.AlthoughtheheightoftheLittleIceAgewasstillaroundthecorner,someevidencesuggeststhattemperatureswerefallingduringthethirteenthcentury.Theenvironmentalchangesassociatedwiththis[20]transition[/20]arenotfullyunderstood,butpeoplelivingclosesttotheSanJuanMountains.tothenortheastofMesaVerde,wereaffectedfirst.[21]Growingfoodattheseelevationsisalwaysdifficultbecauseoftheshortgrowingseason[/21].AstheLittleIceAgeprogressed,farmersprobablymovedtheirfieldstolowerelevations，infringingonthelandsofotherfarmersandpushingpeopletogether,thuscontributingtotheaggregations.ArchaeologistsidentifyacorrespondingshiftinpopulationstowardthesouthandwesttowardMesaVerdeandawayfromhigherelevations.

<23>◆</23><24>◆</24><25>◆</25>Inthefaceofallthesepushes,peopleintheMesaVerdeareahadyetanotherreasontomoveintocommunalvillages:theneedforgreatercooperation.SharingandcooperationwerealmostcertainlypartofearlyPuebloanlife,evenforpeoplelivinginlargelyindependentsingle-householdresidencesscatteredacrossthelandscape.Archaeologistsfindthateventhemostisolatedresidencesduringtheeleventhandtwelfthcenturiesobtainedsomepotteryandprobablyfood,fromsomedistanceaway,whilemajorceremonialeventswereopportunitiesforsharingfoodandcrafts.Scholarsbelievethatthiscooperationallowedpeopletocontendwithapatchyenvironmentinwhichprecipitationandotherresourcesvariedacrossthelandscape:ifyouproducealotoffoodoneyear,youmighttradeitforpotterymadebyadistantallywhoishavingdifficultywithcrops-andthenextyear,theflowofgoodsmightgointheoppositedirection.Butallofthisappearstohavechangedinthethirteenthcentury.Althoughtheclimateremainedasunpredictableaseverbetweenoneyearandthenext,itbecamemuchlesslocallydiverse.Inabadyearforfarming,everyonewasequallyaffected.Nolongerwasithelpfultosharewidely.Instead,themostsensiblethingwouldbeforneighborstocombineeffortstoproduceasmuchfoodaspossible,andthusaggregatedtownswereasensiblearrangement