Why do we call atgenosphere the plastic mantle?

The term "atgenosphere" is often used to describe the plastic mantle because it refers to the semi-fluid layer of the Earth's mantle that behaves like a viscous material under the immense pressure and temperature conditions. This layer is capable of flow, allowing tectonic plates to move on the Earth's surface. The Word "plastic" highlights its ability to deform and change shape over time, similar to how plastic can be molded. Thus, the atgenosphere plays a crucial role in geological processes such as plate tectonics and mantle convection.