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1、英语：Unit4《Exploringplants》背景知识教案（1）（新人教版选修9）TeachingResourcesBackgroundinformationforUnit4Exploringplants1.ImportanceofPlantsPlantsformthebasicfoodstapleforalllifeforms.Theyarethemajorsourceoffoodandoxygenonearth,sincenoanimalcansupplythesenecessarycompon
2、entswithoutplants.Thecattleweeatasbeef,feedongrassesandthefishweeat,consumealgaeandarethereforedependentonplantsforwellbeing.Otherimportantusesofplantsinclude,providingshelterforanimals,providingmaterialsforclothing(cottonfibers),paperproducts,medicinesa
3、ndotherchemicals,producingcoalfromoncelivingplantmaterial,reducingwindspeedandnoiselevels,andreducingsoilerosionandwaterrunoff.Therearemanydifferenttypesofcashcropsthatproducemoneyforfarmers.Oliveoilcomesfromolives,cornoilcomesfromcorn,andpeanutoilcomesf
4、rompeanuts.Typicalagriculturalproductslikecorn,wheat,rye,andriceareallconsideredcashcrops.Coffeeplantsproducebeansthatareusedtomakecoffee;cocaplantsgiveuschocolate;vanillaplantsgrowlongthinbeansthatareusedtoproducevanillaflavoring.Manydrinksandbeverages,
5、likecolaandtea,comefromplants.Rubberfromtreesisalsoacashcrop,asislumber,fruit,vegetables,andcotton.Plantsarealsousedinagriculturetohelpreducewindspeed.Plantingtreesinarowpreventsthewindfromblowingawaythevaluabletopsoil.Intheforest,treesactasshelterforman
6、yorganisms.Plantsarealsoimportantfortheoverallecologyofanarea.Rootshelptostabilizesoilandpreventerosionbywaterrunoff(soilconservation).Plantsarealsoimportantinouratmospherebecausetheyusecarbondioxideandgiveoffoxygenwhiletheyundergophotosynthesis.Plantsar
7、ealsousedintheurbansettingtoreducenoise,produceshade,andtobeautifyanarea.Treesaddvaluetohomesandcommunities.Plantsareessentialtothebalanceofnatureandinpeople'slives.Greenplants,i.e.,thosepossessingchlorophyll,manufacturetheirownfoodandgiveoffoxygeninthep
8、rocesscalledphotosynthesis,inwhichwaterandcarbondioxidearecombinedbytheenergyoflight.Plantsaretheultimatesourceoffoodandmetabolicenergyfornearlyallanimals,whichcannotmanufacturetheirownfood.Besidesfoods(e.g.,grains,fruits,
