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ChinesePopulationGrowthIncreasesinpopulationhaveusuallybeenaccompanied(indeedfacilitated)byanincreaseintrade.IntheWesternexperience,commerceprovidedtheconditionsthatallowedindustrializationtogetstarted,whichinturnledtogrowthinscience,technology,industry,transport,communications,socialchange,andthelikethatwegroupunderthebroadtermof“development.”However,themassiveincreaseinpopulationthatinEuropewasatfirstattributedtoindustrializationstartingintheeighteenthcenturyoccurredalsoandatthesameperiodinChina,eventhoughtherewasnocomparableindustrialization.ItisestimatedthattheChinesepopulationby1600wascloseto150million.ThetransitionbetweentheMingandQingdynasties(theseventeenthcentury)mayhaveseenadecline,butfrom1741to1851theannualfiguresrosesteadilyandspectacularly,perhapsbeginningwith143millionandendingwith432million.Ifweacceptthesetotals,weareconfrontedwithasituationinwhichtheChinesepopulationdoubledinthe50yearsfrom1790to1840.If,withgreatercaution,weassumelowertotalsintheearlyeighteenthcenturyandonly400millionin1850,westillfaceastartlingfact:somethinglikeadoublingofthevastChinesepopulationinthecenturybeforeWesterncontact,foreigntrade,andindustrializationcouldhavehadmucheffect.ToexplainthissuddenincreasewecannotpointtofactorsconstantinChinesesocietybutmustfindconditionsoracombinationoffactorsthatwerenewlyeffectiveinthisperiod.AmongtheseisthealmostcompleteinternalpeacemaintainedunderManchuruleduringtheeighteenthcentury.TherewasalsoanincreaseinforeigntradethroughGuangzhou(southernChina)andsomeimprovementoftransportationwithintheempire.Controlofdisease,likethecheckingofsmallpoxbyvariolationmayhavebeenimportant.Butofmostcriticalimportancewasthefoodsupply.Confrontedwithamultitudeofunreliablefigures,economistshavecomparedthepopulationrecordswiththeaggregatedataforcultivatedlandareaandgrainproductioninthesixcenturiessince1368.AssumingthatChina’spopulationin1400wasabout80million,theeconomistDwightPerkinsconcludesthatitsgrowthto700millionormoreinthe1960swasmadepossiblebyasteadyincreaseinthegrainsupply,whichevidentlygrewfiveorsixtimesbetween1400and1800androseanother50percentbetween1800and1965.Thisincreaseoffoodsupplywasdueperhapshalftotheincreaseofcultivatedarea,particularlybymigrationandsettlementinthecentralandwesternprovinces,andhalftogreaterproductivity—thefarmers’successinraisingmorecropsperunitofland.Thistechnologicaladvancetookmanyforms:onewasthecontinualintroductionfromthesouthofearlier-ripeningvarietiesofrice,whichmadepossibledouble-cropping(theproductionoftwoharvestsperyearfromonefield).Newcropssuchascorn(maize)andsweetpotatoesaswellaspeanutsandtobaccowereintroducedfromtheAmericas.Corn,forinstance,canbegrownonthedrysoilandmarginalhilllandofNorthChina,whereitisusedforfood,fuel,andfodderandprovidessomethinglikeone-seventhofthefoodenergyavailableinthearea.Thesweetpotato,growinginsandysoilandprovidingmorefoodenergyperunitoflandthanothercrops,becamethemainfoodofthepoorinmuchoftheSouthChinaricearea.Productivityinagriculturewasalsoimprovedbycapitalinvestments,firstofallinirrigation.From1400to1900thetotalofirrigatedlandseemstohaveincreasedalmostthreetimes.Therewasalsoagaininfarmtools,draftanimals,andfertilizer,tosaynothingofthepopulationgrowthitselfw,hichincreasedhalfagainasfastascultivatedlandareaandsoincreasedtheratioofhumanhandsavailableperunitofland.Thustherisingpopulationwasfedbyamoreintensiveagriculture,applyingmorelaborandfertilizertotheland.Paragraph1Increasesinpopulationhaveusuallybeenaccompanied(indeedfacilitated)byanincreaseintrade.IntheWesternexperience,commerceprovidedtheconditionsthatallowedindustrializationtogetstarted,whichinturnledtogrowthinscience,technology,industry,transport,communications,socialchange,andthelikethatwegroupunderthebroadtermof“development.”However,themassiveincreaseinpopulationthatinEuropewasatfirstattributedtoindustrializationstartingintheeighteenthcenturyoccurredalsoandatthesameperiodinChina,eventhoughtherewasnocomparableindustrialization.Whichofthesentencesbelowbestexpressestheessentialinformationinthehighlightedsentenceinthepassage?Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.Commerce,industrialization,anddevelopmentarecommonfeaturesoftheWesternexperience.Trade,industrialization,anddevelopmentacceleratedsocialchangeinWesternsocieties.TradeandindustrializationbroughtaboutdevelopmentinWesternsocieties.InWesternsocieties,socialchangeprovidedtheconditionsfordevelopmentinanumberofareas.Theword“attributed”inthepassageisclosestinmeaningtoaccustomedcreditedexposedtransformedParagraph1andParagraph2Increasesinpopulationhaveusuallybeenaccompanied(indeedfacilitated)byanincreaseintrade.IntheWesternexperience,commerceprovidedtheconditionsthatallowedindustrializationtogetstarted,whichinturnledtogrowthinscience,technology,industry,transport,communications,socialchange,andthelikethatwegroupunderthebroadtermof“development."However,themassiveincreaseinpopulationthatinEuropewasatfirstattributedtoindustrializationstartingintheeighteenthcenturyoccurredalsoandatthesameperiodinChina,eventhoughtherewasnocomparableindustrialization.ItisestimatedthattheChinesepopulationby1600wascloseto150million.ThetransitionbetweentheMingandQingdynasties(theseventeenthcentury)mayhaveseenadecline,butfrom1741to1851theannualfiguresrosesteadilyandspectacularly,perhapsbeginningwith143millionandendingwith432million.Ifweacceptthesetotals,weareconfrontedwithasituationinwhichtheChinesepopulationdoubledinthe50yearsfrom1790to1840.If,withgreatercaution,weassumelowertotalsintheearlyeighteenthcenturyandonly400millionin1850,westillfaceastartlingfact:somethinglikeadoublingofthevastChinesepopulationinthecenturybeforeWesterncontact,foreigntrade,andindustrializationcouldhavehadmucheffect.Accordingtoparagraphs1and2,whichofthefollowingistrueofChinesepopulationgrowthbetween1741and1851?ItcoincidedwiththebeginningofindustrializationinChina.ItpromptedspeculationabouttheactualnumberofpeoplelivinginChinainpreviouscenturies.Itcontinuedthesteadygrowthinpopulationofpreviouscenturies.Itoccurredintheabsenceofcertainconditionsgenerallyassociatedwithpopulationgrowth.Accordingtoparagraph2,theestimatedpopulationofChinainthemid1700swas?143million150million400million432millionParagraph3ToexplainthissuddenincreasewecannotpointtofactorsconstantinChinesesocietybutmustfindconditionsoracombinationoffactorsthatwerenewlyeffectiveinthisperiod.AmongtheseisthealmostcompleteinternalpeacemaintainedunderManchuruleduringtheeighteenthcentury.TherewasalsoanincreaseinforeigntradethroughGuangzhou(southernChina)andsomeimprovementoftransportationwithintheempire.Controlofdisease,likethecheckingofsmallpoxbyvariolationmayhavebeenimportant.Butofmostcriticalimportancewasthefoodsupply.Theword“constant”inthepassageisclosestinmeaningtouniquedominantalteredunchangingParagraph3supportsallofthefollowingstatementsabouteighteenth-centuryChinesesocietyEXCEPT:Itwastroubledbyfrequentconflictswithforeignnations.Itimproveditstransportationsystem.Itexperiencedgrowthininternationalcommerce.Itmanagedtopreventthespreadofcertaindiseases.Paragraph4Confrontedwithamultitudeofunreliablefigures,economistshavecomparedthepopulationrecordswiththeaggregatedataforcultivatedlandareaandgrainproductioninthesixcenturiessince1368.AssuminghatChina’spopulationin1400wasabout80million,theeconomistDwightPerkinsconcludesthatitsgrowthto700millionormoreinthe1960swasmadepossiblebyasteadyincreaseinthegrainsupply,whichevidentlygrewfiveorsixtimesbetween1400and1800androseanother50percentbetween1800and1965.Thisincreaseoffoodsupplywasdueperhapshalftotheincreaseofcultivatedarea,particularlybymigrationandsettlementinthecentralandwesternprovinces,andhalftogreaterproductivity—thefarmers’successinraisingmorecropsperunitofland.Paragraph4answerswhichofthefollowingquestionsaboutChina’spopulationgrowthbetween1400and1965?WhichfiguresrelatingtoChina’spopulationgrowthwereunreliable?WhydidDwightPerkinsassumethatChina’spopulationin1400wasabout80million?WhereinChinadidmostofthepopulationincreasetakeplace?WhatfactorsmadeChina’spopulationgrowthbetween1400and1965possible?Theword“aggregate”inthepassageisclosestinmeaningtoavailablereliablecombinedrecordedParagraph5Thistechnologicaladvancetookmanyforms：onewasthecontinualintroductionfromthesouthofearlier-ripeningvarietiesofrice,whichmadepossibledouble-cropping(theproductionoftwoharvestsperyearfromonefield).Newcropssuchascorn(maize)andsweetpotatoesaswellaspeanutsandtobaccowereintroducedfromtheAmericas.Corn,forinstance,canbegrownonthedrysoilandmarginalhilllandofNorthChina,whereitisusedforfood,fuel,andfodderandprovidessomethinglikeone-seventhofthefoodenergyavailableinthearea.Thesweetpotato,growinginsandysoilandprovidingmorefoodenergyperunitoflandthanothercrops,becamethemainfoodofthepoorinmuchoftheSouthChinaricearea.Whatcanbeinferredfromparagraph5abouttheintroductionofcornandsweetpotatoesinChina?Thesecropsrequiredmuchmorecarethanothercrops.Thesecropswereconsumedinlimitedquantities.Thesecropspermittedanexpansionoftheareausedforfarming.ThesecropsbecameavailablealloverChinawithinashortperiodoftime.Paragraph6Productivityinagriculturewasalsoimprovedbycapitalinvestments,firstofallinirrigation.From1400to1900thetotalofirrigatedlandseemstohaveincreasedalmostthreetimes.Therewasalsoagaininfarmtools,draftanimals,andfertilizer,tosaynothingofthepopulationgrowthitselfw,hichincreasedhalfagainasfastascultivatedlandareaandsoincreasedtheratioofhumanhandsavailableperunitofland.Thustherisingpopulationwasfedbyamoreintensiveagriculture,applyingmorelaborandfertilizertotheland.Theword“ratio”inthepassageisclosestinmeaningtoproportionavailabilityimportancecostParagraph5andParagraph6Thistechnologicaladvancetookmanyforms：onewasthecontinualintroductionfromthesouthofearlier-ripeningvarietiesofrice,whichmadepossibledouble-cropping(theproductionoftwoharvestsperyearfromonefield).Newcropssuchascorn(maize)andsweetpotatoesaswellaspeanutsandtobaccowereintroducedfromtheAmericas.Corn,forinstance,canbegrownonthedrysoilandmarginalhilllandofNorthChina,whereitisusedforfood,fuel,andfodderandprovidessomethinglikeone-seventhofthefoodenergyavailableinthearea.Thesweetpotato,growinginsandysoilandprovidingmorefoodenergyperunitoflandthanothercrops,becamethemainfoodofthepoorinmuchoftheSouthChinaricearea.Productivityinagriculturewasalsoimprovedbycapitalinvestments,firstofallinirrigation.From1400to1900thetotalofirrigatedlandseemstohaveincreasedalmostthreetimes.Therewasalsoagaininfarmtools,draftanimals,andfertilizer,tosaynothingofthepopulationgrowthitselfw,hichincreasedhalfagainasfastascultivatedlandareaandsoincreasedtheratioofhumanhandsavailableperunitofland.Thustherisingpopulationwasfedbyamoreintensiveagriculture,applyingmorelaborandfertilizertotheland.WhichofthefollowingisNOTmentionedinparagraphs5and6asoneofthestrategiestheChineseappliedinagriculture?ThegrowingoftwocropsonthesamefieldduringthesameyearTheimprovementofsystemstosupplycropswithwaterTheapplicationofincreasingamountsoffertilizertothelandThereductionintheamountofhumanlaborperunitoflandWhatpurposedoesparagraph5serveinthelargerdiscussionaboutChina’spopulationgrowth?ItprovidesevidenceofChina’semergingforeigntraderelations.ItillustrateshowtheChineseincreasedtheirfoodsupply.Itprovidesevidenceofwhypopulationgrowthwasmostioticeableinthesouth.ItshowshowforeigncropsgraduallygainedgreateracceptanceinChina.Lookatthefoursquares[■]thatindicatewherethefollowingsentencecouldbeaddedtothepassage.OtherdevelopmentsaddressedtheproblemsofdryandsandyareasunsuitableforgrowingChina’snativecrops.Wherewouldthesentencebestfit?Clickonasquare[■]toaddthesentencetothepassage.Thistechnologicaladvancetookmanyforms:onewasthecontinualintroductionfromthesouthofearlier-ripeningvarietiesofrice,whichmadepossibledouble-cropping(theproductionoftwoharvestsperyearfromonefield).■Newcropssuchascorn(maize)andsweetpotatoesaswellaspeanutsandtobaccowereintroducedfromtheAmericas.■Corn,forinstance,canbegrownonthedrysoilandmarginalhilllandofNorthChina,whereitisusedforfood,fuel,andfodderandprovidessomethinglikeone-seventhofthefoodenergyavailableinthearea.■Thesweetpotato,growinginsandysoilandprovidingmorefoodenergyperunitoflandthanothercrops,becamethemainfoodofthepoorinmuchoftheSouthChinaricearea.■Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth2points.Dragyouranswerchoicestothespaceswheretheybelong.Toremoveananswerchoice,clickonit.Toreviewthepassage,clickVIEWTEXT.Overthecenturies,Chinahasexperiencedanextraordinaryincreaseinitspopulation.AnswerChoicesUnderstandingtheexceptionalincreaseinpopulationinChinarequiresgivingupcommonlyheldassumptionsrelativetothephenomenonofpopulationgrowth.TheeconomistDwightPerkinsappliedaparticularstatisticalmethodtodeterminetheincreaseinChina’spopulation.ThesuddenpopulationgrowthinChinastartedinitsnorthernandsouthernprovinces,anditspreadrapidlytothecentralandwesternareasofthecountry.ImprovedtransportationmanagementandenhanceddiseasecontrolcontributedtoChina’spopulationexplosion.TheincreaseinChina’sfoodsupply,whichaffectedpopulationgrowth,wastheresultoftechnologicaldevelopmentsinagricultureandcapitalinvestment.Asteadyincreaseinforeigntradesincethe1400sprovidedtheconditionsnecessaryforlarge-scaleagriculturaldevelopment.TermiteIngenuityTermites,socialinsectswhichliveincoloniesthat,insomespecies,contain2millionindividualsormore,areoftenincorrectlyreferredtoaswhiteants.Buttheyarecertainlynotants.Termites,unlikeants,havegradualmetarnorphosiswithonlythreelifestage：egg,nymph,andadult.Antsandtheothersocialmembersoftheirorder,certainbeesandwasps,havecompletemetarnorphosisinfourlifestages；egg,larva,pupa,andadult.Theworkerandsoldiercastesofsocialants,bees,andwaspsconsistofonlyfemales,alldaughtersofasinglequeenthatmatedsoonaftershematuredandthereafternevermatedagain.Theworkerandsoldiercastesoftermitesconsistofbothmalesandfemales,andthequeenlivespermanentlywithamaleconsort.Sincetermitesaresmallandsoft-bodied,theyeasilybecomedesiccatedandmustliveinmoistplaceswithahighrelativehumidity.Theydobestwhentherelativehumidityintheirnestisabove96percentandthetemperatureisfairlyhigh,anoptimumofabout79°Ffortemperatezonespeciesandabout86°Ffortropicalspecies.Subterraneantermites,thedestructivespeciesthatoccurscommonlythroughouttheeasternUnitedStates,attaintheseconditionsbynestinginmoistsoilthatisincontactwithwood,theironlyfood.Thesurroundingsoilkeepsthenestmoistandtendstokeepthetemperatureatamoreorlessfavorablelevel.Whenitiscoldinwinter,subterraneantermitesmovetoburrowsbelowthefrostline.Sometropicaltermitesaremoreingeniousengineers,constructinghugeabove-groundnestswithbuilt-in“airconditioning”thatkeepsthenestmoist,ataconstanttemperature,andwellsuppliedwithoxygen.AmongthemostarchitecturallyadvancedofthesetermitesisanAfricanspecies,Macroternesnatalensis.RenownedSwissentomologistMartinLuscherdescribedthemoundsofthisfungus-growingspeciesasbeingasmuchas16feettall,16feetindiameterattheirbase,andwithacement-likewallofsoilmixedwithtermitesalivathatisfrom16to23inchesthick.Thethickanddensewallofthemoundinsulatestheinteriormicroclimatefromthevariationsinhumidityandtemperatureoftheoutsideatmosphere.Severalnarrowandrelativelythin-walledridgesontheoutsideofthemoundextendfromnearitsbasealmosttoitstop.Accordingtoluscher,amedium-sizednestofMacrotermeshasapopulationofabout2millionindividuals.Themetabolismofsomanytermitesandofthefungusthattheygrowintheirgardensasfoodhelpskeeptheinteriorofthenestwarmandsuppliessomemoisturetotheairinthenest.Thetermitessaturatetheatmosphereofthenest,bringingittoabout100percentrelativehumidity,bycarryingwaterupfromthesoil.Buthowisthiswell-insulatednestventilated?Itsmanyoccupantsrequireover250quartsofoxygen(morethan1,200quartsofaire)perday.Howcansomuchoxygendiffusethroughthethickwallsofthemound?Eventheporesinthewallarefilledwithwater,whichalmoststopsthediffusionofgases.Theanswerliesintheconstructionofthenest.Theinteriorconsistsofalargecentralcoreinwhichthefungusisgrown,belowitis“cellar”ofemptyspace,aboveitisan“attic”ofemptyspace,andwithintheridgesontheouterwallofthenest,therearemanysmalltunnelsthatconnectthecellarandtheattic.Thewarmairinthefungusgardensrisesthroughthenestuptotheattic.Fromtheattic,theairpassesintothetunnelsintheridgesandflowsbackdowntothecellar.Gases,mainlyoxygencominginandcarbondioxidegoingout,easilydiffuseintooroutoftheridges,sincetheirwallsarethinandtheirsurfaceareaislargebecausetheyprotrudefarourfromthewallofthemound.Thusairthatflowsdownintothecellarthroughtheridgesisrelativelyrichinoxygen,andhaslostmuchofitscarbondioxide.Itsuppliesthenest’sinhabitantswithfreshoxygenasitrisesthroughthefungus-growingareabackuptotheattic.Passage1Termites,socialinsectswhichliveincoloniesthat,insomespecies,contain2millionindividualsormore,areoftenincorrectlyreferredtoaswhiteants.Buttheyarecertainlynotants.Termites,unlikeants,havegradualmetarnorphosiswithonlythreelifestage：egg,nymph,andadult.Antsandtheothersocialmembersoftheirorder,certainbeesandwasps,havecompletemetarnorphosisinfourlifestages;egg,larva,pupa,andadult.Theworkerandsoldiercastesofsocialants,bees,andwaspsconsistofonlyfemales,alldaughtersofasinglequeenthatmatedsoonaftershematuredandthereafternevermatedagain.Theworkerandsoldiercastesoftermitesconsistofbothmalesandfemales,andthequeenlivespermanentlywithamaleconsort.Theauthormentions“whiteants”inthebeginningofthepassageinordertocorrectacommonmisunderstandingabouttermites’introducetheideathattermitesonlytaketheformofantsduringcertainlifestagesarguethatnotallwhiteantsaresocialinsectsIllustratethelargevarietyofinsectspeciesthatliveincoloniesAccordingtoparagraph1,whichofthefollowingistrueabouttermites?Theyareakindofant,buttheyareunlikemostantsinmanyways.Theyformcoloniesthatgrowatfirstandthengraduallydecline.Theirworkersareallmales,andtheirsoldiersareallfemales.Theygothroughalifestatecalledthenymphstage.Passage2Sincetermitesaresmallandsoft-bodied,theyeasilybecomedesiccatedandmustliveinmoistplaceswithahighrelativehumidity.Theydobestwhentherelativehumidityintheirnestisabove96percentandthetemperatureisfairlyhigh,anoptimumofabout79°Ffortemperatezonespeciesandabout86°Ffortropicalspecies.Subterraneantermites,thedestructivespeciesthatoccurscommonlythroughouttheeasternUnitedStates,attaintheseconditionsbynestinginmoistsoilthatisincontactwithwood,theironlyfood.Thesurroundingsoilkeepsthenestmoistandtendstokeepthetemperatureatamoreorlessfavorablelevel.Whenitiscoldinwinter,subterraneantermitesmovetoburrowsbelowthefrostline.Accordingtoparagraph2,termitesneedtoliveinnestswithhighhumidityinordertokeeptheirfoodmoistwithstandcoldtemperaturesinwinterprotecttheirbodiesfromdryingoutkeepnesttemperatureshighTheword“attain”inthepassageisclosetinmeaningtoachieveobserveovercomereflectTheword“ingenious”inthepassageisclosestinmeaningtodeterminedcleverambitioussuccessfulPassage3Sometropicaltermitesaremoreingeniousengineers,constructinghugeabove-groundnestswithbuilt-in“airconditioning”thatkeepsthenestmoist,ataconstanttemperature,andwellsuppliedwithoxygen.AmongthemostarchitecturallyadvancedofthesetermitesisanAfricanspecies,Macroternesnatalensis.RenownedSwissentomologistMartinLuscherdescribedthemoundsofthisfungus-growingspeciesasbeingasmuchas16feettall,16feetindiameterattheirbase,andwithacement-likewallofsoilmixedwithtermitesalivathatisfrom16to23inchesthick.Thethickanddensewallofthemoundinsulatestheinteriormicroclimatefromthevariationsinhumidityandtemperatureoftheoutsideatmosphere.Severalnarrowandrelativelythin-walledridgesontheoutsideofthemoundextendfromnearitsbasealmosttoitstop.Theword“ingenious”inthepassageisclosestinmeaningtodeterminedcleverambitioussuccessfulTheword“Renowned”inthepassageisclosestinmeaningtoSkilledFamousEarlyRevolutionaryAccordingtoparagraph3,thenestsofsometropicaltermitespecieshavetheabilitytoinsulatethemicroclimateinonepartofthenestfromthemicroclimateinanotherpartAllowmoistoutsideairtogetinsideregardlessofwhetheritiswarmorcoolrapidlydecreasethehumidityinsidewhenitgetshotoutsideProvidetheoxygenneededinthenestPassage3&4Sometropicaltermitesaremoreingeniousengineers,constructinghugeabove-groundnestswithbuilt-in“airconditioning”thatkeepsthenestmoist,ataconstanttemperature,andwellsuppliedwithoxygen.AmongthemostarchitecturallyadvancedofthesetermitesisanAfricanspecies,Macroternesnatalensis.RenownedSwissentomologistMartinLuscherdescribedthemoundsofthisfungus-growingspeciesasbeingasmuchas16feettall,16feetindiameterattheirbase,andwithacement-likewallofsoilmixedwithtermitesalivathatisfrom16to23inchesthick.Thethickanddensewallofthemoundinsulatestheinteriormicroclimatefromthevariationsinhumidityandtemperatureoftheoutsideatmosphere.Severalnarrowandrelativelythin-walledridgesontheoutsideofthemoundextendfromnearitsbasealmosttoitstop.Accordingtoluscher,amedium-sizednestofMacrotermeshasapopulationofabout2millionindividuals.Themetabolismofsomanytermitesandofthefungusthattheygrowintheirgardensasfoodhelpskeeptheinteriorofthenestwarmandsuppliessomemoisturetotheairinthenest.Thetermitessaturatetheatmosphereofthenest,bringingittoabout.00percentrelativehumidity,bycarryingwaterupfromthesoil.Accordingtoparagraphs3and4,allofthefollowingaretrueofthenestsofMacroternesnatalensisEXCEPT:Thewallsarebuiltoutofsoilmixedwithtermitesaliva.Thenestscanbeastallastheyarewideatthebase.Theinteriorofthenestiskeptashumidaspossible.Thetermitesusehollow,thin-walledridgestotravelfromonepartofthenesttoanother.Passage4Accordingtoluscher,amedium-sizednestofMacrotermeshasapopulationofabout2millionindividuals.Themetabolismofsomanytermitesandofthefungusthattheygrowintheirgardensasfoodhelpskeeptheinteriorofthenestwarmandsuppliessomemoisturetotheairinthenest.Thetermitessaturatetheatmosphereofthenest,bringingittoabou100percentrelativehumidity,bycarryingwaterupfromthesoil.Accordingtoparagraph4,howdoesthefungusgrownbyMacrotermesnatalensisaffecttheenvironmentofthenest?Itcarrieswaterupfromthesoilintotheinterior.Itdriestheairbyusingupmoistureasitgrows.Itheatsandaddshumiditytotheinsideofthenest.Itlessenstheeffectsofthemetabolismofsomanytermites.Passage5Buthowisthiswell-insulatednestventilated?Itsmanyoccupantsrequireover250quartsofoxygen(morethan1,200quartsofaire)perday.Howcansomuchoxygendiffusethroughthethickwallsofthemound?Eventheporesinthewallarefilledwithwater,whichalmoststopsthediffusionofgases.Theanswerliesintheconstructionofthenest.Theinteriorconsistsofalargecentralcoreinwhichthefungusisgrown,belowitis“cellar”ofemptyspace,aboveitisan“attic”ofemptyspace,andwithintheridgesontheouterwallofthenest,therearemanysmalltunnelsthatconnectthecellarandtheattic.Thewarmairinthefungusgardensrisesthroughthenestuptotheattic.Fromtheattic,theairpassesintothetunnelsintheridgesandflowsbackdowntothecellar.Gases,mainlyoxygencominginandcarbondioxidegoingout,easilydiffuseintooroutoftheridges,sincetheirwallsarethinandtheirsurfaceareaislargebecausetheyprotrudefarourfromthewallofthemound.Thusairthatflowsdownintothecellarthroughtheridgesisrelativelyrichinoxygen,andhaslostmuchofitscarbondioxide.Itsuppliesthenest’sinhabitantswithfreshoxygenasitrisesthroughthefungus-growingareabackuptotheattic.Accordingtoparagraph5,whatdoesthethinnessoftheridgewallsmakepossible?TheconcentrationofcoolairinthecellarTheconstructionofexceptionallylongtunnelsTheevendistributionofoxygenfromattictocellarThediffusionofgasesintoandoutoftheridgesAccordingtoparagraph5,whathappenstotheairintheridgetunnelsofMacrotermesnatalensisnests?Itbecomesmorehumidaswatervapordiffusesintothetunnels.Itlosescarbondioxideandgainsoxygen.Itreachestheinteriorofthenestthroughporesinthewalls.Itmovesinthesamedirectionastheairinthecenterofthenest.Paragraph5supportswhichofthefollowingabouttheairthatflowsthroughtheinteriorofaMacrotermesnatalensismound?Ithasahigherconcentrationofoxygeninthecellarthanintheattic.Itisthesametemperatureastheairontheoutsideofthemound.Itcontainsover250quartsofoxygenwhichcirculatecontinuously.Itismosthumidinthecellarandgraduallylosesmoistureasitrisestotheattic.Lookatthefoursquares[■thatindicatewherethefollowingsentencecouldbeaddedtothepassage.Ifnotthroughthewallsoritspores,howdoesoxygenenterthenestatall,sincethenesthasaclosedsurface?Wherewouldthesentencebestfit?Clickonasquare[■]toaddthesentencetothepassage.Buthowisthiswell-insulatednestventilated?Itsmanyoccupantsrequireover250quartsofoxygen(morethan1,200quartsofaire)perday.Howcansomuchoxygendiffusethroughthethickwallsofthemound?[■]Eventheporesinthewallarefilledwithwater,whichalmoststopsthediffusionofgases.[■]Theanswerliesintheconstructionofthenest.[■]Theinteriorconsistsofalargecentralcoreinwhichthefungusisgrown,belowitis“cellar”ofemptyspace,aboveitisan“attic”ofemptyspace,andwithintheridgesontheouterwallofthenest,therearemanysmalltunnelsthatconnectthecellarandtheattic.[■]Thewarmairinthefungusgardensrisesthroughthenestuptotheattic.Fromtheattic,theairpassesintothetunnelsintheridgesandflowsbackdowntothecellar.Gases,mainlyoxygencominginandcarbondioxidegoingout,easilydiffuseintooroutoftheridges,sincetheirwallsarethinandtheirsurfaceareaislargebecausetheyprotrudefarourfromthewallofthemound.Thusairthatflowsdownintothecellarthroughtheridgesisrelativelyrichinoxygen,andhaslostmuchofitscarbondioxide.Itsuppliesthenest’sinhabitantswithfreshoxygenasitrisesthroughthefungus-growingareabackuptotheattic.Directions:Anintroductorysentenceforabriefsummaryofthepassageisprovidedbelow.CompletethesummarybyselectingtheTHREEanswerchoicesthatexpressthemostimportantideasinthepassage.Somesentencesdonotbelonginthesummarybecausetheyexpressideasthatarenotpresentedinthepassageorareminorideasinthepassage.Thisquestionisworth3points.Dragyouranswerchoicestothespaceswheretheybelong.Toremoveananswerchoice,clickonit.Toreviewthepassage,clickVIEWTEXT.Termitesaresocialinsectsthatliveinlarge,oftenelaboratelyconstructednests.AnswerChoicesAlthoughtermitesresembleantsintermsofsize,metarmorphosis,andsocialorganization,theyactuallybelongtoadifferentorderofinsects.Sometermitesbuildtheirnestsunderground,whileotherconstructabove-groundstructureswiththick,insulatingwall.Sometermitespeciesgrowafungusintheirnestssothatitwillpurifytheairbytakingincarbondioxideandgivingoffoxygen.Termitesaresensitivetodrynessandtochangesintemperature,tshoeirnestsaredesignedtominimizethesefactors.Whethertheylieabovegroundorbelowground,termitenestsmustincludespecialporesthatallowairtoenterthenests.ThenestsofMacrotermesnatalensisconsisbfaseriesofchambersandtunnelsthatallowforthecirculationofairandtheexchangeofoxygenandcarbondioxide.ClimateandUrbanDevelopmentFormorethanahundredyears,ithasbeenknownthatcitiesaregenerallywarmerthansurroundingruralareas.Thisregionofcitywarmth,knownastheurbanheatisland,caninfluencetheconcentrationofairpollution.However,beforewelookatitsinfluence,let’sseehowtheheatislandactuallyforms.Theurbanheatislandisduetoindustrialandurbandevelopment.Inruralareas,alargepartoftheincomingsolarenergyisusedinevaporatingwaterfromvegetationandsoil.Incities,wherelessvegetationandexposedsoilexist,themajorityoftheSun’senergyisabsorbedbyurbanstructuresandasphal