哈工大考博英語(yǔ)真題含答案

GeneralEnglishAdmissionTestForNon-EnglishMajor

Ph.D.program

(HarbinInstituteofTechnology)

PassageOne

Questionsl—8arebasedonthefollowingpassage:

Inthetwodecadesbetween1910and1930,overtenpercentoftheBlackpopulationofthe

UnitedStateslefttheSouth,wherethepreponderanceoftheBlackpopulationhadbeenlocated,

andmigratedtonorthernstates,withthelargestnumbermoving,itisclaimed,between1916and

1918.Ithasbeenfrequentlyassumed,butnotproved,thatthemajorityofthemigrantsinwhat

hascometobecalledtheGreatMigrationcamefromruralareasandweremotivatedbytwo

concurrentfactors:thecollapseofthecottonindustryfollowingthebollweevilinfestation,which

beganin1898,andincreaseddemandintheNorthforlaborfollowingthecessationofEuropean

immigrationcausedbytheoutbreakoftheFirstWorldWarin1914.Thisassumptionhasledto

theconclusionthatthemigrants?subsequentlackofeconomicmobilityintheNorthistiedto

ruralbackground,abackgroundthatimpliesunfamiliaritywithurbanlivingandalackof

industrialskills.

ButthequestionofwhoactuallylefttheSouthhasneverbeenrigorouslyinvestigated.

Althoughnumerousinvestigationsdocumentanexodusfromruralsouthernareastosouthern

citiespriortotheGreatMigration,noonehasconsideredwhetherthesamemigrantsthenmoved

ontonortherncities.In1910over600,000Blackworkers,ortenpercentoftheBlackworkforce,

reportedthemselvestobeengagedin"'manufacturingandmechanicalpursuits/9thefederalcensus

categoryencompassingtheentireindustrialsector.TheGreatMigrationcouldeasilyhavebeen

madeupentirelyofthisgroupandtheirfamilies.Itisperhapssurprisingtoarguethatan

employedpopulationcouldbeenticedtomove,butanexplanationliesinthelaborconditions

thenprevalentintheSouth.

Aboutthirty-fivepercentoftheurbanBlackpopulationintheSouthwasengagedinskilled

trades.Somewerefromtheoldartisanclassofslaveryblacksmiths,masons,carpenters-which

hadhadamonopolyofcertaintrades,buttheyweregraduallybeingpushedoutbycompetition,

mechanization,andobsolescence.Theremainingsixty-fivepercent,morerecentlyurbanized,

workedinnewlydevelopedindustries-tobacco,lumber,coalandironmanufacture,andrailroads.

WagesintheSouth,however,werelow,andBlackworkerswereaware,throughlaborrecruiters

andtheBlackpress,thattheycouldearnmoreevenasunskilledworkersintheNorththanthey

couldasartisansintheSouth.Afterthebollweevilinfestation,urbanBlackworkersfaced

competitionfromthecontinuinginfluxofbothBlackandWhiteruralworkers,whoweredriven

toundercutthewagesformerlypaidforindustrialfobs.Thus,amovenorthwouldbeseenas

advantageoustoagroupthatwasalreadyurbanizedandsteadilyemployed,andtheeasy

conclusiontyingtheirsubsequenteconomicproblemsintheNorthtotheirruralbackground

comesintoquestion.

l.Theauthorindicatesexplicitlythatwhichofthefollowingrecordshasbeenasourceof

informationinherinvestigation?

(A)UnitedStatesImmigrationServicereportsfrom1914to1930.

(B)Payrollsofsouthernmanufacturingfirmsbetween1910and1930.

(C)Thevolumeofcottonexportsbetween1898and1910.

(D)Thefederalcensusof1910.

2.1nthepassage,theauthoranticipateswhichofthefollowingasapossibleobjectiontoher

argument?

ItisuncertainhowmanypeopleactuallymigratedduringtheGreatMigration.

TheeventualeconomicstatusoftheGreatMigrationmigrantshasnotbeenadequatelytraced.

Itisnotlikelythatpeoplewithsteadjobswouldhavereasontomovetoanotherareaofthe

country.

Itisnottruethattheterm""manufacturingandmechanicalpursuits“actuallyencompassesthe

entireindustrialsector.

3.Accordingtothepassage,whichofthefollowingistrueofwagesinsoutherncitiesin1910?

(A)Theywerebeingpushedlowerasaresultofincreasedcompetition.

(B)Theyhadbeguntorisesothatsouthernindustrycouldattractruralworkers.

(C)Theyhadincreasedforskilledworkersbutdecreasedforunskilledworkers.

(D)Theyhadincreasedinlargesoutherncitiesbutdecreasedinsmallsoutherncities.

4.TheauthorciteseachofthefollowingaspossibleinfluencesinaBlackworker'sdecisionto

migratenorthintheGreatMigrationEXCEPT.

(A)wagelevelsinnortherncities

(B)laborrecruiters

(C)competitionfromruralworkers

(D)votingrightsinnorthernstates

5.Itcanbeinferredfromthepassagethatthe“easyconclusion^^mentionedinline16ofthelast

paragraphisbasedonwhichofthefollowingassumptions?

(A)Peoplewhomigratefromruralareastolargecitiesusuallydosoforeconomicreasons.

(B)Mostpeoplewholeaveruralareastotakejobsincitiesreturntoruralareasassoonasitis

financiallypossibleforthemtodoso.

(C)Peoplewithruralbackgroundsarelesslikelytosucceedeconomicallyincitiesthanarethose

withurbanbackgrounds.

(D)Mostpeoplewhowereonceskilledworkersarenotwillingtoworkasunskilledworkers.

6.Theprimarypurposeofthepassageisto.

Supportanalternativetoanacceptedmethodology

Presentevidencethatresolvesacontradiction

Introducearecentlydiscoveredsourceofinformation

Challengeawidelyacceptedexplanation

7.Accordingtoinformationinthepassage,whichofthefollowingisacorrectsequenceofgroups

ofworkers,fromhighestpaidtolowestpaid,intheperiodbetween1910and1930?

ArtisansintheNorth;artisansintheSough;unskilledworkersintheNorth;unskilledworkersin

thesouth.

ArtisansintheNorthandSouth;unskilledworkersintheNorth;unskilledworkersintheSouth.

ArtisansintheNorth;unskilledworkersintheNorth;artisansintheSouth.

ArtisansintheNorthandSouth;unskilledurbanworkersintheNorth;unskilledruralworkersin

theSouth.

8.Thematerialinthepassagewouldbemostrelevanttoalongdiscussionofwhichofthe

followingtopics?

ThereasonsforthesubsequenteconomicdifficultiesofthosewhoparticipatedintheGreat

Migration.

TheeffectofmigrationontheregionaleconomiesoftheUnitedStatesfollowingtheFirstWorld

War.

ThetransitionfromaruraltoanurbanexistenceforthosewhomigratedintheGreatMigration.

ThetransformationoftheagriculturalSouthfollowingthebollweevilinfestation.

PassageTwo

Question9—17arebasedonthefollowingpassage:

Priorto1975,unioneffortstoorganizepublic-sectorclericalworker,mostofwhomarewomen,

weresomewhatlimited.Thefactorsfavoringunionizationdrivesseemtohavebeeneitherthe

presenceoflargenumbersofworkers,asinNewYorkCity,tomakeitworththeeffort,orthe

concentrationofsmallnumbersinoneortwolocations,suchasahospital,tomakeitrelatively

easy.Receptivitytounionizationontheworkers,partwasalsoaconsideration,butwhenthere

werelargenumbersinvolvedortheclericalworkersweretheonlyunorganizedgroupina

jurisdiction,themultioccupationalunionswouldoftentrytoorganizethemregardlessofthe

workers5initialreceptivity.Thestrategicreasoningwasbased,first,ontheconcernthatpoliticians

andadministratorsmightplayoffunionizedagainstnonunionizedworkers,and,second,onthe

convictionthatafullyunionizedpublicworkforcemeantpower,bothatthebargainingtableand

inthelegislature.Inlocalitieswhereclericalworkerswerefewinnumber,werescatteredin

severalworkplaces,andexpressednointerestinbeingorganized,unionsmoreoftenthannot

ignoredtheminthepre-1975period.

Butsincethemid-1970's,adifferentstrategyhasemerged.In1977,34percentofgovernment

clericalworkerswererepresentedbyalabororganization,comparedwith46percentof

governmentprofessionals,44percentofgovernmentblue-collarworkers,and41percentof

governmentserviceworkers.Sincethen,however,thebiggestincreasesinpublic-sector

unionizationhavebeenamongclericalworkers.Between1977and1980,thenumberofunionized

governmentworkersinblue-collarandserviceoccupationsincreasedonlyabout1.5percent,

whileinthewhite-collaroccupationstheincreasewas20percentandamongclericalworkersin

particular,theincreasewas22percent.

Whataccountsforthisupsurgeinunionizationamongclericalworkers?First,morewomen

haveenteredtheworkforceinthepastfewyears,andmoreofthemplantoremainworkinguntil

retirementage.Consequently,theyareprobablymoreconcernedthantheirpredecessorswere

aboutjobsecurityandeconomicbenefits.Also,thewomen'smovementhassucceededin

legitimizingtheeconomicandpoliticalactivismofwomenoftheirownbehalf,therebyproducing

amorepositiveattitudetowardunions.Theabsenceofanycomparableincreaseinunionization

amongprivate-sectorclericalworker,however,identifiestheprimarycatalyst-thestructural

changeinthemultioccupationalpublic-sectorunionsthemselves.Overthepasttwentyyears,the

occupationaldistributionintheseunionshasbeensteadilyshiftingfrompredominantly

blue-collartopredominantlywhite-collar.Becausetherearefarmorewomeninwhite-collarjobs,

anincreaseintheproportionoffemalemembershasaccompaniedtheoccupationalshiftandhas

alteredunionpolicy-makinginfavoroforganizingwomenandaddressingwomen'sissues.

9.Accordingtothepassage,thepublic-sectorworkerswhoweremostlikelytobelongtounionsin

1977were.

(A)professionals

(B)managers

(C)clericalworkers

(D)serviceworkers

lO.Theauthorcitesunioneffortstoachieveafullyunionizedworkforce(line11-15)inorderto

accountforwhy.

(A)politiciansmighttrytoopposepublic-sectorunionorganizing

(B)public-sectorunionshaverecentlyfocusedonorganizingwomen

(C)earlyorganizingeffortsoftenfocusedonareaswheretherewerelargenumbersofworkers

(D)unionssometimestriedtoorganizeworkersregardlessoftheworkers5initialinterestin

unionization

11.Theauthor'sclaimthat,sincethemid-1970's,anewstrategyhasemergedintheunionization

ofpublic-sectorclericalworkers(line19)wouldbestrengthenediftheauthor.

(A)describedmorefullytheattitudesofclericalworkerstowardlaborunions

(B)comparedtheorganizingstrategiesemployedbyprivate-sectorunions

(C)explainedwhypoliticiansandadministratorssometimesopposeunionizationofclerical

workers

(D)showedthatthefactorsthatfavoredunionizationdrivesamongtheseworkerspriorto1975

havedecreasedinimportance

12.Accordingtothepassage,intheperiodpriorto1975,eachofthefollowingconsiderations

helpeddeterminewhetheraunionwouldattempttoorganizeacertaingroupofclericalworkers

EXCEPT.

(A)thenumberofclericalworkersinthatgroup

(B)thenumberofwomenamongtheclericalworkersinthatgroup

(C)whethertheclericalworkersinthatareawereconcentratedinonework-placeorscattered

overseveralwork-places

(D)thedegreetowhichtheclericalworkersinthatgroupwereinterestedinunionization

13.Theauthorstatesthatwhichofthefollowingisaconsequenceofthewomen'smovementof

recentyears?

(A)Anincreaseinthenumberofwomenenteringtheworkforce.

(B)Astructuralchangeinmultioccupationalpublic-sectorunions.

(C)Amorepositiveattitudeonthepartofwomentowardunions.

(D)Anincreaseintheproportionofclericalworkersthatarewomen.

14.Themainconcernofthepassageisto.

(A)advocateparticularstrategiesforfutureeffortstoorganizecertainworkersintolaborunions

(B)explaindifferencesintheunionizedproportionsofvariousgroupsofpublic-sectorworkers

(C)evaluatetheeffectivenessofcertainkinksoflaborunionsthatrepresentpublic-sector

workers

(D)analyzedandexplainanincreaseinunionizationamongacertaincategoryofworkers

15.Theauthorimpliesthatiftheincreaseinthenumberofwomenintheworkforceandthe

impactofthewomen'smovementwerethemaincausesoftheriseinunionizationof

public-sectorclericalworkers,then.

morewomenwouldholdadministrativepositionsinunions

morewomenwhoholdpoliticalofficeswouldhavepositiveattitudestowardlaborunions

therewouldbeanequivalentriseinunionizationofprivate-sectorclericalworkers

unionswouldhaveshownmoreinterestthantheyhaveinorganizingwomen

16.Theauthorsuggeststhatitwouldbedisadvantageoustoaunionif.

(A)manyworkersinthelocalitywerenotunionized

(B)theunioncontributedtopoliticalcampaigns

(C)theunionincludedonlypublic-sectorworkers

(D)theunionincludedworkersfromseveraljurisdictions

17.Theauthorimpliesthat,incomparisonwithworkingwomentoday,womenworkinginthe

yearspriortothemid-1970'sshowedagreatertendencyto.

(A)prefersmallerworkplaces

(B)expressapositiveattitudetowardlaborunions

(C)maximizejobsecurityandeconomicbenefits

(D)quitworkingpriorofretirementage

PassageThree

Questions18—24arebasedonthefollowingpassage:

StudiesoftheWeddellsealinthelaboratoryhavedescribedthephysiologicalmechanismsthat

allowthesealtocopewiththeextremeoxygendeprivationthatoccursduringitslongestdives,

whichcanextend500metersbelowtheocean'ssurfaceandlastforover70minutes.Recentfield

studies,however,suggestthatduringmoretypicaldivesinthewild,thisseal'sphysiological

behaviorisdifferent.

Inthelaboratory,whenthesealdivesbelowthesurfaceofthewaterandstopsbreathing,its

heartbeatsmoreslowly,requiringlessoxygenanditsarteriesbecomeconstricted,ensuringthat

theseaFsbloodremainsconcentratednearthoseorgansmostcrucialtoitsabilitytonavigate

underwater.Thesealessentiallyshutsofftheflowofbloodtootherorgans,whicheitherstop

functioninguntilthesealsurfacesorswitchtoananaerobic(oxygen-independent)metabolism.

Thelatterresultsintheproductionoflargeamountsoflacticacidwhichcanadverselyaffectthe

PHoftheseaFsbloodbutsincetheanaerobicmetabolismoccursonlyinthosetissueswhichhave

beenisolatedfromtheseal'sbloodsupply,thelacticacidisreleasedintotheseal'sbloodonly

afterthesealsurfaces,whenthelungs,liver,andotherorgansquicklycleartheacidfromthe

seafsbloodstream.

Recentfieldstudies,however,revealthatondivesinthewild,thesealusuallyheadsdirectly

foritspreyandreturnstothesurfaceinlessthantwentyminutes.Theabsenceofhighlevelsof

lacticacidintheseal'sbloodaftersuchdivessuggeststhatduringthem,theseal'sorgansdonot

resorttotheanaerobicmetabolismobservedinthelaboratory,butaresuppliedwithoxygenfrom

theblood.Theseal'slongerexcursionsunderwater,duringwhichitappearstobeeitherexploring

distantroutesorevadingapredator,doevokethedivingresponseseeninthelaboratory.Butwhy

dotheseal'slaboratorydivesalwaysevokethisresponse,regardlessoftheirlengthordepth?

Somebiologistsspeculatethatbecauseinlaboratorydivesthesealisforciblysubmerged,itdoes

notknowhowlongitwillremainunderwaterandsopreparesfortheworst.

18.Thepassageprovidesinformationtosupportwhichofthefollowinggeneralizations?

Observationsofanimals5physiologicalbehaviorinthewildarenotreliableunlessverifiedby

laboratorystudies.

Itisgenerallylessdifficulttoobservethephysiologicalbehaviorofananimalinthewildthanin

thelaboratory.

Theleveloflacticacidinananimal'sbloodislikelytobehigherwhenitissearchingforprey

thanwhenitsevadingpredators.

Thephysiologicalbehaviorofanimalsinalaboratorysettingisnotalwaysconsistentwiththeir

physiologicalbehaviorinthewild.

19.ItcanbeinferredfromthepassagethatbydescribingtheWeddellsealaspreparingtcforthe

worsf5lines31-32,biologistsmeanthatit.

preparestoremainunderwaterfornolongerthantwentyminutes

exhibitsphysiologicalbehaviorsimilartothatwhichcharacterizesdivesinwhichitheadsdirectly

foritsprey

exhibitsphysiologicalbehaviorsimilartothatwhichcharacterizesitslongestdivesinthewild

beginstoexhibitpredatorybehavior

20.Thepassagesuggeststhatduringlaboratorydives.ThePHoftheWeddellseal'sbloodisnot

adverselyaffectedbyproductionoflacticacidbecause.

(A)onlythoseorgansthatareessentialtotheseal'sabilitytonavigateunder-waterreverttoan

anaerobicmechanism.

(B)thesealtypicallyrevertstoananaerobicmetabolismonlyattheveryendofthedive

(C)organsthatreverttoananaerobicmetabolismaretemporarilyisolatedfromtheseal's

bloodstream

(D)thesealremainssubmergedforonlyshortperiodsoftime

21.Whichofthefollowingbestsummarizesthemainpointofthepassage?

(A)Recentfieldstudieshaveindicatedthatdescriptionsofthephysiologicalbehaviorofthe

Weddellsealduringlaboratorydivesarenotapplicabletoitsmosttypicaldivesinthewild.

(B)TheWeddellsealhasdevelopedanumberofuniquemechanismsthatenableittoremain

submergedatdepthsofupto500metersforupto70minutes.

(C)Theresultsofrecentfieldstudieshavemadeitnecessaryforbiologiststoreviseprevious

perceptionsofhowtheWeddellsealbehavesphysiologicallyduringitslongestdivesinthe

wild.

(D)HowtheWeddellsealrespondstooxygendeprivationduringitslongestdivesappearsto

dependonwhetherthesealissearchingforpreyoravoidingpredatorsduringsuchdives.

22.Accordingtotheauthor,whichofthefollowingistrueofthelaboratorystudismentionedin

line1?

(A)TheypresentanoversimplifiedaccountofmechanismsthattheWeddellsealreliesonduring

itslongestdivesinthewild.

(B)TheyprovideevidencethatunderminestheviewthattheWeddellsealreliesonananaerobic

metabolismduringitsinthewild.

(C)TheyarebasedontheassumptionthatWeddellsealsrarelyspendmorethantwentyminutes

underwateronatypicaldiveinthewild.

(D)TheyprovideanaccurateaccountofthephysiologicalbehaviorofWeddellsealsduring

thosedivesinthewildinwhichtheyareeitherevadingpredatorsorexploringdistantroutes.

23.TheauthorciteswhichofthefollowingascharacteristicoftheWeddellseal'sphysiological

behaviorduringdivesobservedinthelaboratory?

I.Adecreaseintherateatwhichtheseal'sheartbeats.

ILAconstrictionoftheseal'sarteries.

III.Adecreaseinthelevelsoflacticacidintheseal'sblood.

IV.Atemporaryhaltinthefunctioningofcertainorgans.

(A)IandIIIonly

(B)IandIVonly

(C)IIandIIIonly

(D)I,II,andIVonly

24.ThepassagesuggeststhatbecauseWeddellsealsareforciblysubmergedduringlaboratory

dives,theydowhichofthefollowing?

Exhibitthephysiologicalresponsesthatarecharacteristicofthelongerdivestheyundertakeinthe

wild.

Copewhitoxygendeprivationlesseffectivelythandoontypicaldivesinthewild.

Producesmalleramountsoflacticacidthantheydoontypicaldivesinthewild.

Navigatelesseffectivelythantheydoontypicaldivesinthewild.

PassageFour

Questions25—30arebasedonthefollowingpassage:

Australianresearchershavediscoveredelectroreceptors(sensoryorgansdesignedtorespondto

electricalfields)clusteredatthetipofthespinyanteater'ssnout.Theresearchersmadethis

discoverybyexposingsmallareasofthesnouttoextremelyweakelectricalfieldsandrecording

thetransmissionofresultingnervousactivitytothebrain.Whileitistruethattactilereceptors,

anotherkindofsensoryorganontheanteater'ssnout,canalsorespondtoelectricalstimuli,such

receptorsdosoonlyinresponsetoelectricalfieldstrengthsabout1,000timesgreaterthanthose

knowntoexciteelectroreceptors.

Havingdiscoveredtheelectroreceptors,researchersarenowinvestigatinghowanteatersutilize

suchasophisticatedsensorysystem.Inonebehavioralexperiment,researcherssuccessfully

trainedananteatertodistinguishbetweentwotroughsofwater,onewithaweakelectricalfield

andtheotherwithnone.Suchevidenceisconsistentwithresearcher^hypothesisthatanteaters

useelectroreceptorstodetectelectricalsignalsgivenoffbyprey;however,researchersasyethave

beenunabletodetectelectricalsignalsemanatingfromtermitemounds,wherethefavoritefood

ofanteaterslive.Still,researchershaveobservedanteatersbreakingintoanestofantsatan

obliqueangleandquicklylocatingnestingchambers.Thisabilityquicklytolocateunseenprey

suggests,accordingtotheresearchers,thattheanteaterswereusingtheirelectroreceptorstolocate

thenestingchambers.

25.Accordingtothepassage,whichofthefollowingisacharacteristicthatdistinguishes

electroreceptorsfromtactilereceptors?

(A)Themannerinwhichelectroreceptorsrespondtoelectricalstimuli.

(B)Thetendencyofelectroreceptorstobefoundinclusters.

(C)Theunusuallocationsinwhichelectroreceptorsarefoundinmostspecies.

(D)Theamountofelectricalstimulationrequiredtoexciteelectroreceptors.

26.Whichofthefollowingcanbeinferredabouttheexperimentdescribedinthefirstparagraph?

(A)Researchershaddifficultyverifyingtheexistenceofelectroreceptorsintheanteaterbecause

electroreceptorsrespondtosuchanarrowrangeofelectricalfieldstrengths.

(B)Researchersfoundthatthelevelofnervousactivityintheanteater'sbrainincreased

dramaticallyasthestrengthoftheelectricalstimuluswasincreased.

(C)Researchersfoundthatsomeareasoftheanteater'ssnoutwerenotsensitivetoaweak

electricalstimulus.

(D)Researchersfoundthattheanteater'stactilereceptorsweremoreeasilyexcitedbyastrong

electricalstimulusthanweretheelectroreceptors.

27.Theauthorofthepassagemostprobablydiscussesthefunctionoftatilereceptors(lines6一9)

inorderto.

(A)eliminateandalternativeexplanationofanteaters?responsetoelectricalstimuli

(B)highlightatypeofsensoryorganthathasafunctionidenticaltothatofelectroreceptors

(C)pointoutaseriouscomplicationittheresearchonelectroreceptorsinanteaters

(D)suggestthattactilereceptorsassistelectroreceptorsinthedetectionofelectricalsignals

28.Whichofthefollowingcanbeinferredaboutanteatersfromthebehavioralexperiment

mentionedinthesecondparagraph?

Theyareunabletodistinguishbetweenstimulidetectedbytheirelectroreceptorsandstimuli

detectedbytheirtactilereceptors.

Theyareunabletodistinguishbetweentheelectricalsignalsemanatingfromtermitemoundsand

thoseemanatingfromantnests.

Theycanbetrainedtorecognizeconsistentlythepresenceofaparticularstimulus.

Theyreactmorereadilytostrongthantoweakstimuli.

29.Thepassagesuggeststhattheresearchersmentionedinthesecondparagraphwhoobserved

anteatersbreakintoanestofantswouldmostlikelyagreewithwhichofthefollowing

statements?

(A)Theeventtheyobservedwasatypicalandmaynotreflecttheusualhuntingpracticesof

anteaters.

(B)Itislikelythattheanteaterslocatedtheants'nestingchamberswithouttheassistanceof

electroreceptors.

(C)Anteaterspossessaverysimplesensorysystemforusinlocatingprey.

(D)Thespeedwithwhichtheanteaterslocatedtheirpreyisgreaterthanwhatmightbeexpected

onthebasisofchancealone.

30.Whichofthefollowing,iftrue,wouldmoststrengthenthehypothesismentionedinlines

15—16?

(A)Researchersareabletotrainanteaterstobreakintoanundergroundchamberthatisemitting

astrongelectricalsignal.

(B)Researchersareabletodetectaweakelectricalsignalemanatingfromthenestingchamber

ofanantcolony.

(C)Anteatersareobservedtakingincreasinglylongeramountsoftimetolocatethenesting

chambersofants.

(D)Anteatersareobservedusingvariousanglestobreakintonestsofants.

PassageFive

Questions31—35arebasedonthefollowingpassage:

Coralreefsareoneofthemostfragile,biologicallycomplex,anddiversemarineecosystemon

Earth.Thisecosystemisoneofthefascinatingparadoxesofthebiosphere:howdoclear,andthus

nutrient-poorwaterssupportsuchprolificandproductivecommunities?Partoftheanswerlies

withinthetissuesofthecoralsthemselves.Symbioticcellsofalgaeknownaszoozanthellaecarry

outphotosynthesisusingthemetabolicwastesofthecoraltherebyproducingfoodforthemselves,

fortheircorals,hosts,andevenforothermembersofthereefcommunity.Thissymbioticprocess

allowsorganismsinthereefcommunitytousesparsenutrientresourceefficiently.

Unfortunatelyforcoralreefs,however,avarietyofhumanactivitiesarecausingworldwide

degradationofshallowmarinehabitatsbyaddingnutrientstothewater.Agriculture,slash一and

-burnlandclearing,sewagedisposalandmanufacturingthatcreateswasteby-productsall

increasenutrientloadsinthesewaters.Typicalsymptomsofreefdeclinearedestabilized

herbivorepopulationsandanincreasingabundanceofalgaeandfiletr-feedinganimals.Declines

inreefcommunitiesareconsistentwithobservationsthatnutrientinputisincreasingindirect

proportiontogrowinghumanpopulations,therebythreateningreefcommunitiessensitiveto

subtlechangesinnutrientinputtotheirwaters.

3l.Thepassageisprimarilyconcernedwith.

(A)describingtheeffectsofhumanactivitiesonalgaeincoralreefs

(B)explaininghowhumanactivitiesareposingathreattocoralreefcommunities

(C)discussingtheprocessbywhichcoralreefsdeteriorateinnutrient-poorwaters

(D)explaininghowcoralreefsproducefoodforthemselves

32.Thepassagesuggestswhichofthefollowingaboutcoralreefcommunities?

Coralreefcommunitiesmayactuallybemorelikelytothriveinwatersthatarerelativelylowin

nutrients.

Thenutrientsonwhichcoralcommunitiesthriveareonlyfoundinshallowwaters.

Humanpopulationgrowthhasledtochangingoceantemperatures,whichthreatenscoralreef

co