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1、英语：Unit4《Exploringplants》背景知识教案（1）（新人教版选修9）TeachingResourcesBackgroundinformationforUnit4ExploringplantsImportanceofPlantsPlantsformthebasicfoodstapleforalllifeforms.Theyarethemajorsourceoffoodandoxygenonearth,sincenoanimalcansupplythesenecessarycomponentswithoutplants.Thecattleweeatasbeef,feedon
2、grassesandthefishweeat,consumealgaeandarethereforedependentonplantsforwellbeing.Otherimportantusesofplantsinclude,providingshelterforanimals,providingmaterialsforclothing(cottonfibers),paperproducts,medicinesandotherchemicals,producingcoalfromoncelivingplantmaterial,reducingwindspeedandnoiselevel
3、s,andreducingsoilerosionandwaterrunoff.Therearemanydifferenttypesofcashcropsthatproducemoneyforfarmers.Oliveoilcomesfromolives,cornoilcomesfromcorn,andpeanutoilcomesfrompeanuts.Typicalagriculturalproductslikecorn,wheat,rye,andriceareallconsideredcashcrops.Coffeeplantsproducebeansthatareusedtomake
4、coffee;cocaplantsgiveuschocolate;vanillaplantsgrowlongthinbeansthatareusedtoproducevanillaflavoring.Manydrinksandbeverages,likecolaandtea,comefromplants.Rubberfromtreesisalsoacashcrop,asislumber,fruit,vegetables,andcotton.Plantsarealsousedinagriculturetohelpreducewindspeed.Plantingtreesinarowprev
5、entsthewindfromblowingawaythevaluabletopsoil.Intheforest,treesactasshelterformanyorganisms.Plantsarealsoimportantfortheoverallecologyofanarea.Rootshelptostabilizesoilandpreventerosionbywaterrunoff(soilconservation).Plantsarealsoimportantinouratmospherebecausetheyusecarbondioxideandgiveoffoxygenwh
6、iletheyundergophotosynthesis.Plantsarealsousedintheurbansettingtoreducenoise,produceshade,andtobeautifyanarea.Treesaddvaluetohomesandcommunities.Plantsareessentialtothebalanceofnatureandinpeople'slives.Greenplants,i.e.,thosepossessingchlorophyll,manufacturetheirownfoodandgiveoffoxygenintheprocess
7、calledphotosynthesis,inwhichwaterandcarbondioxidearecombinedbytheenergyoflight.Plantsaretheultimatesourceoffoodandmetabolicenergyfornearlyallanimals,whichcannotmanufacturetheirownfood.Besidesfoods(e.g.,grains,fruits,an
