Answer: Viscous property
Explanation: The asthenosphere is the layer that lies below the crust. This layer is generally viscous, where the rocks floats due to deformation. It is the top part of the mantle and generation of convection current pushes the materials to move, thereby breaking the crust, causing it to move in convergent or divergent direction or slide past each other. The composition is same for both the lithosphere and the asthenosphere but it has its viscous property.