byLeighClarkCover,p.12,©JeffHunter/TheImageBank/GettyImages;p.3,©HorizonInternationalImagesLimited/Alamy;p.4,©ErnestManewal/IndexStockImagery;p.6,©DanGotshall/VisualsUnlimited;p.7,©Corbis;p.8,(tr)©JamesBeveridge/VisualsUnlimited,(cr)©BruceWatkins/EarthScenes,(bc)©MartySnyderman/VisualsUnlimited;p.9,©ReinhardDirscherl/VisualsUnlimited;p.10,©FREDBAVENDAM/MindenPictures;p.11,©StevenWolperandOdysseyProductions,Inc.;p.13,©StephenFrink/ScienceFaction/GettyImages;p.14,©AndyCaulfield/TheImageBank/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.PrintedinChinaISBN10:0-15-351542-2ISBN13:978-0-15-351542-2OrderingOptionsISBN10:0-15-351214-8(Grade4AdvancedCollection)ISBN13:978-0-15-351214-8(Grade4AdvancedCollection)ISBN10:0-15-358132-8(packageof5)ISBN13:978-0-15-358132-8(packageof5)Ifyouhavereceivedthesematerialsasexaminationcopiesfreeofcharge,HarcourtSchoolPublishersretainstitletothematerialsandtheymaynotberesold.Resaleofexaminationcopiesisstrictlyprohibitedandisillegal.Possessionofthispublicationinprintformatdoesnotentitleuserstoconvertthispublication,oranyportionofit,intoelectronicformat.1234567891098512111009080706byLeighClarkImagineaworldbeneaththeseafilledwithfishandplantsineverycoloroftherainbow.Thisunderseaworldisoneofthesevennaturalwondersoftheworld.ItistheGreatBarrierReefinAustralia.Thereefissolargethatastronautscanseeitfromspace!TheGreatBarrierReefismadeupofhundredsofsmallerreefs.Areefislikeawallthatgrowsintheocean.Reefsaremadeupofthousandsofcorals,ana...
