What characteristic does the asthenosphere have?

The asthenosphere is characterized by its ability to behave like soft plastic, allowing it to flow slowly over geological time. This unique property is due to the high temperatures and pressures within this layer of the Earth, which make the rocks there partially molten and less rigid compared to the underlying lithosphere. This plasticity enables tectonic plates located on top of the asthenosphere to move, facilitating processes such as continental drift and plate tectonics.

The other choices do not accurately describe the asthenosphere. While it is not completely rigid like the lithosphere, nor is it completely molten, it exists in a state that is more fluid than solid. It is also not primarily composed of sediment; instead, it consists mainly of mantle rock materials that undergo gradual deformation under stress, enabling the geodynamic processes critical to the movement of Earth’s tectonic plates.