bySunitaAptebySunitaApteCover,©Explorer/PhotoResearchers,Inc.;p.4,©APPhoto/YahyaAhmed;p.5,©SteveMcCurry/MagnumPhotos;p.6,©APPhoto/YahyaAhmed;p.7,©LowellGeorgia/CORBIS;p.8,©AndersPettersson/GettyImages;p.9,©AndersPettersson/GettyImages;p.10,©PaulSchutzer/TimeLifePictures/GettyImages;p.11,©UNIVERSAL/THEKOBALCOLLECTION;p.12,©SteveMcCurry/MagnumPhotos;p.13,©RobertvanderHilst/CORBIS;p.14,©AFPPHOTO/FILE/PASCALGUYOT/GettyImages.Copyright©byHarcourt,Inc.Allrightsreserved.Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicormechanical,includingphotocopy,recording,oranyinformationstorageandretrievalsystem,withoutpermissioninwritingfromthepublisher.RequestsforpermissiontomakecopiesofanypartoftheworkshouldbeaddressedtoSchoolPermissionsandCopyrights,Harcourt,Inc.,6277SeaHarborDrive,Orlando,Florida32887-6777.Fax:407-345-2418.HARCOURTandtheHarcourtLogoaretrademarksofHarcourt,Inc.,registeredintheUnitedStatesofAmericaand/orotherjurisdictions.PrintedintheUnitedStatesofAmericaISBN10:0-15-350576-1ISBN13:978-0-15-350576-8OrderingOptionsISBN10:0-15-350336-X(Grade6Below-LevelCollection)ISBN13:978-0-15-350336-8(Grade6Below-LevelCollection)ISBN10:0-15-357583-2(packageof5)ISBN13:978-0-15-357583-9(packageof5)Ifyouhavereceivedthesematerialsasexaminationcopiesfreeofcharge,HarcourtSchoolPublishersretainstitletothematerialsandtheymaynotberesold.Resaleofexaminationcopiesisstrictlyprohibitedandisillegal.Possessionofthispublicationinprintformatdoesnotentitleuserstoconvertthispublication,oranyportionofit,intoelectronicformat.12345678910179121110090807063Anoilwellisonfire.Theflamesshootuphundredsoffeetintotheair.Thickblacksmokefillsthesky.Let’sfindoutmoreaboutoilwells.Oilwellsarecreatedbydrillingholesintotheearthinoil-richareas.Mostoilwellshavemanymillionsofgallonsofoil,whichburnseasily.Thefirecouldburnuntileverydropofthatoilisgone.Thelongerthefiregoes,theworsethingsget.Thefireisbadfortheenvironment.Itmakestheairunsafeforpeoplewholivenearby.Thecompanyth...
