(a) The Earth is nearly spherical and has a corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger structure consisting of three layers:
(i) a thin corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger; which is the least dense layer.
(ii) a liquid corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger extending almost halfway to the Earth's centre which has all the properties of a solid except that it can flow very slowly like a 'plastic liquid'.
The third layer (iii), is the corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger, which is about half of the Earth's radius, made of weakly magnetic corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger and mainly strongly magnetic corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger. It outer part is corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger and the inner part is corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger.

(b) The overall corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger of the Earth is much greater than the mean densities of the rocks which form the crust. This indicates that the inner layers of the Earth are made of corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger and corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger dense material than that of the crust.

(c) At the surface of the Earth corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger rocks usually lie on top of older rocks. Sediments contain evidence for how they were corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger (e.g. layers formed by discontinuous deposition, corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger marks formed by currents or waves) and corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger tell us what plants and animals were alive at the time.

(d) Sedimentary rock layers are often found tilted, folded, corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger (fractured) and sometimes even turned corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger down. This shows that the Earth's crust is corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger and has been subjected to very large corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger. Large scale movements of the Earth's crust can cause mountain ranges to form very slowly over millions of years. These replace corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger mountain ranges worn down by weathering and corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger.

(e) Most corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger rocks are associated with the Earth movements (corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger activity) which created present-day and ancient mountain belts. They are evidence of them being heated to corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger and squeezed at high corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger when created in these mountain-building processes.

(f) Rocks formed from cooled solidifying corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger from the very hot mantle are called corecrustdensitydepositeddifferenterosionfaultedforcesfossilshighigneousironlayeredliquidmagmamantlemetamorphicmorenickelolderpressureripplesedimentarysolidtectonictemperaturesunstableupsideyounger rocks.