Here's a breakdown:
* Crust: The outermost layer of the Earth, composed of relatively light and rigid rocks. It's divided into oceanic crust (thinner and denser) and continental crust (thicker and less dense).
* Mantle: The layer beneath the crust, making up the largest part of the Earth. It's mostly solid rock but behaves like a very viscous fluid over long periods.
* Lithosphere: The rigid outermost layer of the Earth, composed of the crust and the uppermost part of the mantle. It's broken into large pieces called tectonic plates.
* Asthenosphere: The layer beneath the lithosphere, within the upper mantle. It's partially molten and behaves like a viscous fluid, allowing the tectonic plates to move on top of it.
Therefore, the lithosphere, which includes both the crust and the uppermost mantle, is the solid structure that forms the tectonic plates.
