TPO 22.docx

TPO 22.docx

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TPO22

TPO22

1.Accordingtoparagraph1,eachofthefollowingistrueofSpartinaalrernifloraEXCEPT:

A.Itrarelyflowersinsaltmarshes.

B.Itgrowswellinintertidalzones.

C.Itiscommonlyreferredtoascordgrass.

D.ItoccursnaturallyalongtheGulfCoastandtheAtlanticcoastoftheUnitedStates.

2.Accordingtoparagraph2,amajorreasonwhynaturalsaltmarshesaresoproductiveisthattheyare

A.inhabitedbylong-livedseaweedandmarshgrassesthatreproducegradually

B.keptclearofexcessplantmaterialbythetides

C.regularlysuppliedwithhighlevelsofnutrients

D.hometoawidevarietyofdifferentspeciesofgrasses

3.Whichofthesentencesbelowbestexpresstheessentialinformationinthehighlightedsentenceinthepassage?

Incorrectchoiceschangethemeaninginimportantwaysorleaveoutessentialinformation.

A.Insectsfeedonlyondeadcordgrass,whilemostothermarshinhabitantsfeedonlivecordgrass.

B.Themarshisagoodhabitatforinsects,butarelativelypooroneforbirdsandanimals.

C.Althoughcordgrassprovidesfoodforbirdsandanimals,itgivesinsectsbothfoodandaplacetolive.

D.Cordgrassprovidesfoodfornumerousinsects,birds,andotheranimals.

4.Whatistheorganizationalstructureofparagraph3?

A.ItmakesageneralclaimaboutSpartinaandthenprovidesspecificevidencetodefendthatclaimagainstobjectionstotheclaim.

B.ItpresentsageneralcharacterizationofSpartinaandthendescribesparticularfeaturesonwhichthischaracterizationisbased.

C.ItreportsawidelyheldviewaboutSpartinaandthenconsidersevidencebothforandagainstthatview.

D.ItpresentsageneralhypothesisaboutSpartinaandthenlistsspecificevidencethatdisputesthathypothesis.

5.Theword"exceedingly"inthepassageisclosestinmeaningto

A.unusually

B.dangerously

C.surprisingly

D.highly

6.Accordingtoparagraph3,onereasonthatSpaninaisabletocompeteinmarshenvironmentssosuccessfullyisitsabilityto

A.alterthesubstrateinwhichitgrows

B.convertsulfidesintoausableformofsulfur

C.growandproduceseedswhilefloatingonthesurfaceofthewater

D.producecarbondioxidewithgreatefficiency

7.Paragraph4suggeststhatwhereSpaninaoccursnaturally,anestablishedstandofitwilleventually

A.createconditionsinwhichitcannolongersurvive

B.getwashedawaybywaterflowingthroughthedeepchannelsthatformaroundit

C.becomeadaptedtobrackishwater

D.takeoverothergrassspeciesgrowinginthearea

8.Accordingtoparagraph4,initsnaturalhabitats,Spaninahelpsestuariesby

A.controllingmarshlanddecline

B.decreasingthesubstrateelevation

C.reducingthebrackishnessofthewater

D.increasingtheflowofwaterintotheestuary

9.Theword"modifies"inthepassageisclosestinmeaningto

A.creates

B.changes

C.growson

D.breaksdown

10.Theword"Efforts"inthepassageisclosestinmeaningto

A.Laws

B.Suggestions

C.Attempts

D.Failures

11.Accordingtoparagraph5,Spaninanegativelyaffectswildlifeinestuariesby

A.trappingfishandwaterfowlinsediment

B.preventingoystersfromtransplantingsuccessfully

C.turningmudflatsintohighmarshesandsaltmeadows

D.expandingthemarshyfringesofsaltmeadows

12.Accordingtoparagraph6,eachofthefollowingmethodshasbeenusedinattemptstocontrolSpaninaEXCEPT

A.floodingplants

B.cuttingplantsdownrepeatedly

C.applyingherbicides

D.introducingpredatoryinsects

13.Lookatthefoursquares[Ⓐ][Ⓑ][Ⓒ]and[Ⓓ]thatindicatewherethefollowingsentencecouldbeaddedtothepassage.

Spartinaisparticularlyabletotoleratehighsalinitiesbecausesaltglandsonthesurfaceoftheleavesremovethesaltfromtheplantsap.

Wherewouldthesentencebestfit?

14.

Spaninaalrerniflora,orcordgrass,isthedominantnativespeciesinsaltmarshesalongtheAtlanticcoastandtheGulfCoastoftheUnitedStates.

Clickon3answers.

A.Spartinaisverywelladaptedtoconditionsinsaltmarshes,whereitplaysavaluableroleinstabilizingthemandmakingthemhighlyproductivemarinehabitats.

B.Spartinaexpandsbygrowingrootsystemsthatfloatonthewater’ssurfaceanddescendunderground,whereitfindsthenutrientsthatitneedstogerminate.

C.AsaresultofitsspreadinWashingtonStateoverthepasthundredyears.Spartinahasnowbecomeathreattonativeoystersbyreleasingsedimentsthatcontainsulfidesintothewaters.

D.ThedeadleavesofSpartinabecomefoodforawidevarietyofmarineorganisms.

E.Outsideitsnativeregions,Spartinacanposeseriousproblemsbyturningmudflatsintohighmarshesthatareinhospitabletomanynativefishandbirds.

F.Spartinahasphysiologicaladaptationsthatallowittogrowinenvironmentswhereotherplantscannot,makingitaverystrongcompetitorthatisdifficulttocontrolonceitisestablished.

Spartina

Spartinaalterniflora,knownascordgrass,isadeciduous,perennialfloweringplantnativetotheAtlanticcoastandtheGulfCoastoftheUnitedStates.Itisthedominantnativespeciesofthelowersaltmarshesalongthesecoasts,whereitgrowsintheintertidalzone（theareacoveredbywatersomepartsofthedayandexposedothers）.

Thesenaturalsaltmarshesareamongthemostproductivehabitatsinthemarineenvironment.Nutrient-richwaterisbroughttothewetlandsduringeachhightide,makingahighrateoffoodproductionpossible.Astheseaweedandmarshgrassleavesdie,bacteriabreakdowntheplantmaterial,andinsects,smallshrimplikeorganisms,fiddlercrabs,andmarshsnailseatthedecayingplanttissue,digestit,andexcretewasteshighinnutrients.Numerousinsectsoccupythemarsh,feedingonlivingordeadcordgrasstissue,andredwingblackbirds,sparrows,rodents,rabbits,anddeerfeeddirectlyonthecordgrass.Eachtidalcyclecarriesplantmaterialintotheoffshorewatertobeusedbythesubtidalorganisms.

Spartinaisanexceedinglycompetitiveplant.Itspreadsprimarilybyundergroundstems;coloniesformwhenpiecesoftherootsystemorwholeplantsfloatintoanareaandtakerootorwhenseedsfloatintoasuitableareaandgerminate.Spartinaestablishesitselfonsubstratesrangingfromsandandsilttogravelandcobbleandistolerantofsalinitiesrangingfromthatofnearfreshwater（0.05percent）tothatofsaltwater（3.5percent）.Becausetheylackoxygen,marshsedimentsarehighinsulfidesthataretoxictomostplants.Spartinahastheabilitytotakeupsulfidesandconvertthemtosulfate,aformofsulfurthattheplantcanuse;thisabilitymakesiteasierforthegrasstocolonizemarshenvironments.AnotheradaptiveadvantageisSpartina’sabilitytousecarbondioxidemoreefficientlythanmostotherplants.

ThesecharacteristicsmakeSpartinaavaluablecomponentoftheestuarieswhereitoccursnaturally.Theplantfunctionsasastabilizerandasedimenttrapandasanurseryareaforestuarinefishandshellfish.Onceestablished,astandofSpartinabeginstotrapsediment,changingthesubstrateelevation,andeventuallythestandevolvesintoahighmarshsystemwhereSpartinaisgraduallydisplacedbyhigher-elevation,brackish-waterspecies.Aselevationincreases,narrow,deepchannelsofwaterformthroughoutthemarsh.AlongtheeastcoastSpartinaisconsideredvaluableforitsabilitytopreventerosionandmarshlanddeterioration;itisalsousedforcoastalrestorationprojectsandthecreationofnewwetlandsites.

SpartinawastransportedtoWashingtonStateinpackingmaterialsforoysterstransplantedfromtheeastcoastin1894.Leavingitsinsectpredatorsbehind,thecordgrasshasbeenspreadingslowlyandsteadilyalongWashington’stidalestuariesonthewestcoast,crowdingoutthenativeplantsanddrasticallyalteringthelandscapebytrappingsediment.Spartinamodifiestidalmudflats,turningthemintohighmarshesinhospitabletothemanyfishandwaterfowlthatdependonthemudflats.ItisalreadyhamperingtheoysterharvestandtheDungenesscrabfishery,anditinterfereswiththerecreationaluseofbeachesandwaterfronts.SpartinahasbeentransplantedtoEnglandandtoNewZealandforlandreclamationandshorelinestabilization.InNewZealandtheplanthasspreadrapidly,changingmudflatswithmarshyfringestoextensivesaltmeadowsandreducingthenumberandkindsofbirdsandanimalsthatusethemarsh.

EffortstocontrolSpartinaoutsideitsnaturalenvironmenthaveincludedburning,flooding,shadingplantswithblackcanvasorplastic,smotheringtheplantswithdredgedmaterialsorclay,applyingherbicide,andmowingrepeatedly.LittlesuccesshasbeenreportedinNewZealandandEngland;WashingtonState’smanagementprogramhastriedmanyofthesemethodsandispresentlyusingtheherbicideglyphosphatetocontrolitsspread.Workhasbeguntodeterminethefeasibilityofusinginsectsasbiologicalcontrols,buteffectivebiologicalcontrolsareconsideredyearsaway.Evenwithamassiveeffort,itisdoubtfulthatcompleteeradicationofSpartinafromnonnativehabitatsispossible,forithasbecomeanintegralpartoftheseshorelinesandestuariesduringthelast100to200years.

Spartinaisanexceedinglycompetitiveplant.ⒶItspreadsprimarilybyundergroundstems;coloniesformwhenpiecesoftherootsystemorwholeplantsfloatintoanareaandtakerootorwhenseedsfloatintoasuitableareaandgerminate.ⒷSpartinaestablishesitselfonsubstratesrangingfromsandandsilttogravelandcobbleandistolerantofsalinitiesrangingfromthatofnearfreshwater（0.05percent）tothatofsaltwater（3.5percent）.ⒸBecausetheylackoxygen,marshsedimentsarehighinsulfidesthataretoxictomostplan