In a model of earth's layers that is determined by physical properties, how might the atmosphere be classified? would it be part of the lithosphere or a seperate layer?

Generally, the Earth is divided into spheres which include the "lithosphere" (land), "hydrosphere" (water), "biosphere" (living things), and "atmosphere" (air). The earth is divided into three layers based on chemical composition and these are the core, mantle and crust. In addition, the earth is also divided into physical properties which include lithosphere, athenosphere, mesosphere, outer core and inner core. Based on the given details, we can conclude that the atmosphere cannot be part of the lithosphere but instead, it is classified in a separate layer. The lithosphere only consists the outermost, rigid part of the Earth, which are the crust and the mantle. Hope this answer helps.