Describe the relationship of the Earth's lithosphere to the asthenosphere. The asthenosphere is composed of rigid plates that "float" on top of the lithosphere. The lithosphere is composed of rigid plates that "float" on top of the asthenosphere. The lithosphere is a solid wall around the asthenosphere, and they move as one unit. The asthenosphere is found in the Earth's core and is protected by the lithosphere.

The asthenosphere is the weak and easily deformed layer of the Earth that acts as a "lubricant" for the tectonic plates to slide over.

Option (2)

Explanation:

The earth is comprised of numerous small and large plates which are commonly known as the lithospheric plates. The plates comprising the continental portion refer to the continental plate and the plate that contains the large oceanic body is referred to as the oceanic plates. These plates collectively form the lithosphere which is the hard and resistant part of the earth.

These plates are continuously floating over the less dense layer of the asthenosphere, which is a part of the upper mantle. This layer is less dense and thought the rocks here are solid but they tend to flow in response to deformation. This movement of plates over the asthenosphere layer is possible due to the generation of convection current in the mantle. These convection currents are formed because of the heat energy provided from the interior of the earth.

Thus, the Plate Tectonic theory explains this motion of lithospheric plates over the asthenosphere.

Hence, the correct answer is option (2).