Middle School 5 and 6

The thin, outermost layer of the Earth, or the uppermost part of the lithosphere.

• mantle

• core

• crust

• mesosphere

The layer of the Earth between the crust and the core.

• crust

• core

• mantle

• astenosphere

The central, spherical part of the Earth below the mantle.

• crust

• core

• mantle

• lithosphere

The liquid layer of the Earth's core that lies beneath the mantle and surrounds the inner core.

• inner core

• outer core

• mesosphere

• lithosphere

The solid, dense center of the Earth.

• mesosphere

• outer core

• asthenosphere

• inner core

The theory that continents can drift apart from one another and have done so in the past.

• continental drift

• seafloor spreading

• mid-ocean ridges

• plate tectonics

The process by which new oceanic lithosphere is created at mid-ocean ridges as older materials are pulled away from the ridge.

• continental drift

• seafloor spreading

• mid-ocean ridges

• plate tectonics

A long mountain chain that forms in the ocean floor were tectonic plates pull apart; usually extends along the center of ocean basins.

• seafloor spreading

• mid-ocean ridges

• continental drift

• plate tectonics

The theory that the Earth's lithosphere is divided into tectonic plates that move around on top of the asthenosphere.

• continental drift

• seafloor spreading

• mid-ocean ridges

• plate tectonics

The boundary between two colliding tectonic plates.

• convergent boundary

• subduction zone

• divergent boundary

• transform boundary