托福阅读真题集锦(六)

HowtheimmunesystemofanimalsandthedefensemechanismsofplantsdifferThephrase"subjectto"inline1isclosestinmeaningtosusceptibletoclassifiedbyattractivetostrengthenedbyTheword"puncture"inline8isclosestinmeaningtopiercepinchsurroundcover.Theword"which"inline12referstotissuessubstancesbarriersinsectsWhichofthefollowingsubstancesdoestheauthormentionasNOTnecessarilybeingtoxictotheColoradobeetle?resinstanninsglycosidesalkaloidsWhydoestheauthormention"glycoproteins"inline17?tocompareplantdefensemechanismstotheimmunesystemofanimalstointroducethediscussionofactivedefensemechanismsinplantstoillustratehowchemicalsfunctioninplantdefensetoemphasizetheimportaneeofphysicalbarriersinplantdefenseTheword"dramatic"inline23couldbestbereplacedbystrikingaccurateconsistentappealingWhereinthepassagedoestheauthordescribeanactiveplant-defensereaction?Lines1-3Lines4-6Lines13-15Lines24-27Thepassagemostprobablycontinueswithadiscussionoftheoriesonthebasisofpassiveplantdefensehowchemicalsinhibitaparasiticrelationship.howplantsproducetoxicchemicalstheprinciplesofthehypersensitiveresponse.PASSAGE12AmongthespeciesofseabirdsthatusethewindsweptcliffsoftheAtlanticcoastofCanadainthesummertomate,layeggs,andreartheiryoungarecommonmurres,Atlanticpuffins,black-leggedkittiwakes,andnorthern gannets.Ofallthebirdsonthesecliffs,theblack-leggedkittiwakegullisthebestsuitedfornestingonnarrowledges.Althoughitsnestinghabitsaresimilartothoseofgullsthatnestonflatground,thereareanumberofimportantdifferencesrelatedtothecliff-nestinghabit.Theadvantageofnestingoncliffsistheimmunityitgivesfromfoxes,whichcannotscalethesheerrocks,andfromravensandotherspeciesofgulls,whichhavedifficultyinlandingonnarrowledgestostealeggs.Thisimmunityhasbeenfollowedbyarelaxationofthedefenses,andkittiwakesdonotreacttopredatorsnearlyasfiercelyasdoground-nestinggulls.AcolonyofBonaparte'sgullsrespondstotheappearaneeofapredatory herringgullbyflyingupasagroupwithaclamorofalarmcalls,followedbyconcertedmobbing,butkittiwakessimplyignoreherringgulls,sincetheyposelittlethreattonestsoncliffs.Neitherdokittiwakesattempttoconcealtheirnest.Mostgullskeepthenestareaclearofdroppings,andremoveemptyeggshellsafterthechickshavehatched,sothatthelocationofthenestisnotgivenaway.Kittiwakesdefecateovertheedgeofthenest, whichkeepsitclean,butthispractice,aswell astheirtendencytoleavethenestlitteredwitheggshells,makesitslocationveryconspicuous.Ontheotherhand,nestingonanarrowledgehasitsownpeculiarproblems,andkittiwakebehaviorhasbecomeadaptedtoovercomethem.Thefemalekittiwakesitswhenmating,whereasothergullsstand,sothepairwillnotoverbalaneeandfallofftheledge.Thenestisadeepcup,madeofmudorseaweed,toholdtheeggssafely,comparedwiththeshallowscrapeofothergulls,andthechicksareremarkablyimmobileuntil fullygrown.Theydonotrunfromtheirnestswhenapproached,andiftheyshouldcomeneartothecliffedge,theyinstinctivelyturnback.Whataspectofthekittiwakegulldoesthepassagemainlydiscuss?ItsdefensivebehaviorItinteractionswithothergullspeciesItsnestinghabitsItsphysicaldiffereneefromothergullspeciesTheword"rear"inline2isclosestinmeaningtovisitwatchreverseraiseTheword"scale"inline8isclosestinmeaningtoclimbavoidapproachmeasureTheword"immunity"inline9isclosestinmeaningtodistaneetransitionprotectionreminderWhyisitdifficultforravenstostealthekittiwakes'eggs?Thekittiwakescanseetheravensapproachingthenest.Theravenscannotlandonthenarrowledgeswherekittiwakesnest.Thekittiwakes'eggsaretoobigfortheravenstocarry.Thefemalekittiwakesrarelyleavethenest.Theauthormentionsthateggshellslitteraroundthenestsofkittiwakesinordertodemonstratethatkittiwakesarenotconcernedaboutpredatorsprovehowbusykittiwakesareincaringfortheiroffspringshowasimilaritytoothertypesofgullsillustratekittiwakes'lackofconcernfortheirchicksAccordingtothepassage,itcanbeinferredthatwhichofthefollowingbirdsconcealtheirnest?Bonaparte'sgullsAtlanticpuffinsKittiwakegullsNortherngannetsTheword"it"inline17referstolocationedgenestpracticeThe