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1、2019-2020年高中英语Unit4《Exploringplants》背景知识教案（1）新人教版选修9TeachingResourcesBackgroundinformationforUnit4ExploringplantsImportanceofPlantsPlantsformthebasicfoodstapleforalllifeforms.Theyarethemajorsourceoffoodandoxygenonearth,sincenoanimalcansupplythesenecessaryponentswit
2、houtplants.Thecattleweeatasbeef,feedongrassesandthefishweeat,consumealgaeandarethereforedependentonplantsforwellbeing.Otherimportantusesofplantsinclude,providingshelterforanimals,providingmaterialsforclothing(cottonfibers),paperproducts,medicinesandotherchemicals,p
3、roducingcoalfromoncelivingplantmaterial,reducingwindspeedandnoiselevels,andreducingsoilerosionandwaterrunoff.Therearemanydifferenttypesofcashcropsthatproducemoneyforfarmers.Oliveoilesfromolives,cornoilesfromcorn,andpeanutoilesfrompeanuts.Typicalagriculturalproducts
4、likecorn,wheat,rye,andriceareallconsideredcashcrops.Coffeeplantsproducebeansthatareusedtomakecoffee;cocaplantsgiveuschocolate;vanillaplantsgrowlongthinbeansthatareusedtoproducevanillaflavoring.Manydrinksandbeverages,likecolaandtea,efromplants.Rubberfromtreesisalsoa
5、cashcrop,asislumber,fruit,vegetables,andcotton.Plantsarealsousedinagriculturetohelpreducewindspeed.Plantingtreesinarowpreventsthewindfromblowingawaythevaluabletopsoil.Intheforest,treesactasshelterformanyorganisms.Plantsarealsoimportantfortheoverallecologyofanarea.R
6、ootshelptostabilizesoilandpreventerosionbywaterrunoff(soilconservation).Plantsarealsoimportantinouratmospherebecausetheyusecarbondioxideandgiveoffoxygenwhiletheyundergophotosynthesis.Plantsarealsousedintheurbansettingtoreducenoise,produceshade,andtobeautifyanarea.T
7、reesaddvaluetohomesandmunities.Plantsareessentialtothebalanceofnatureandinpeople'slives.Greenplants,i.e.,thosepossessingchlorophyll,manufacturetheirownfoodandgiveoffoxygenintheprocesscalledphotosynthesis,inwhichwaterandcarbondioxidearebinedbytheenergyoflight.Plants
8、aretheultimatesourceoffoodandmetabolicenergyfornearlyallanimals,whichcannotmanufacturetheirownfood.Besidesfoods(e.g.,grains,fruits,andvegetables)
