Certainanimalsandplantsdevelopcharacteristicsthathelpthemdealwiththeirenvironmentbetterthanothersoftheirkind.Thisnaturalbiologicalprocessiscalledadaptation.Amongthesuperiorcharacteristicsdevelopedthroughadaptationarethosethatmayhelpingettingfoodorshelterinprovidingprotectionandinproducingandprotectingtheyoung.Thatresultsinthegradualdevelopmentofmoreandmoreorganisms（smalllivingthings）thatarebetterfittedtotheirenvironments.

Eachlivingthingisadaptedtoitswayoflifeinageneralwaybuteachisadaptedespeciallytoitsowndistinctclass(kind).Aplantforexampledependsuponitsrootstofixitselffirmlyandtoabsorbwaterandinorganicchemicals(无机化学物).Itdependsuponitsgreenleavesforusingthesun'senergytomakefoodfrominorganicchemicals.Thesearegeneraladaptationscommontomostplants.Inadditiontherearespecialadaptationsthatonlycertainkindsofplantshave.

Manyanimalshaveadaptationsthathelpthemescapefromtheirenemies.Someinsectsarehiddenbytheirbodycolororshapeandmanylooklikealeaforalittlebranch.Thecoatsofdeerarecoloredtomixwiththesurroundings.Manyanimalshavetheabilitytoremaincompletelystillwhenanenemyisnear.

　Organismshaveagreatvarietyofwaysofadapting.Theymayadaptintheirstructurefunctionandgenetics;intheirdevelopmentandproductionoftheyoung;andinotherrespects.Anorganismmaycreateitswonenvironmentasdowarm-bloodedmammalswhichhavetheabilitytoadjustbodyheatexactlytomaintaintheiridealtemperaturedespitechangingweather.Usuallyadaptationsareanadvantagebutsometimesanorganismissowelladaptedtoaparticularenvironmentthatifconditionschangeitfindsitdifficultorimpossibletoreadapttothenewconditions.

40.Someplantsandanimalsdevelopsuperiorcharacteristicssothattheymay　.

　A.helpothersoftheirkindgetfoodshelterandotherthingsneeded

　B.surviveeveninextremelysevereconditions

　C.becomebetteradaptedtotheenvironmentsthanothersoftheirkind

　D.resultintheevolutionandproductionofmoreintelligentorganisms

41.Inthefirstparagraphtheword"environments"cou