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1、21.SoilsTherearemanydifferentkindsofsoils.Differentsoilshavedifferenttypesofrockandmineralsinthem.Somesoilshavemorewaterinthemthanothers.Somesoilsmighthavemoreplantandanimalmaterialinthem,too.Differentkindsofsoilsarefoundindifferentpartsoftheworld.Thereareseveralkindsofsoi
2、lsfoundintheUnitedStates.Insomeareas,thesoilhasalotofclay.Othersoilsareverysandy.Loamisakindofsoilthathasagoodmixtureofclayandsand.Insomeplaces,soillayersareverythick.Lotsofplantsgrowinplaceswithathicksoillayer.Indryandwindyplacessoillayersaremuchthinner.Layersofsoilonmoun
3、tainsarethinbecausegravitypullsthesoildownhill.Thetypeofsoilinaparticularplaceaffectswhatkindsofplantscangrowthere.22.CrisisLifeisacontest!Whowillwin?Abluebirdandsparrowbothcompeteforspacetobuildtheirnests.Afast-growingmapletreeandslower-growingdogwoodcompeteforthesunlight
4、theybothneed.Oilcompeteswithcoalandnuclearpowerasanenergysourceforelectricpowerplants!Thereisaproblem.Thereisalimitedamountofspaceforbirds,sunlightfortrees,andenergyforpeople!Ifwedonotcutbackonourusesofsomeofourresources,somedaytheywillbegone!Howcanweuseenergytodayandknoww
5、ewillhaveenoughtogoaroundinthefuture?Wecanchoosealternate,orreplacement,energyresources.Itforthequalityofreviewsandreview.Article26threview(a)theCCRAcompliance,whethercopiesofchecks;(B)whetherdoubleinvestigation;(C)submissionofprogramcompliance,investigationorexaminationof
6、whetherviewsareclear;(D)theborrower,guarantorloanstakestheearthmillionsofyearstocreatecoal,oil,andgas.Theyarenonrenewableresources.Solarenergy,windenergyandwaterenergyarerenewableresources.Ittakestheearthmillionsofyearstocreatecoal,oil,andgas.Theyarenonrenewableresources.S
7、olarenergy,windenergyandwaterenergyarerenewable.Whatotherwayscanweconserveourresources?Howcanwemakesurethereisalwaysenoughtogoaround?23.America’sWorstSurpriseDecember7,1941wasoneoftheworstdaysinAmericanhistory.NearlyallAmericanswhoareoldenoughtorememberthatdaycanstillremem
8、berwhattheyweredoingatthemomenttheyheard“thenews”.ThenewswasthatAmericahadbeenattacked!Sh