In geography, taking a slice through a structure to see inside is called a cross section ... Constructive plate margins close constructive plate marginAn area where two tectonic plates are ...

Plate tectonics is the theory that Earth's outer layer is made up of plates, which have moved throughout Earth's history. The theory explains the how and why behind mountains, volcanoes ...

Plate tectonic theory shows that the crust of the ... It is also the thickest section at approximately 2900 km thick. The mantle is made up of different layers. The upper mantle is hard but ...