Solution:Based on chemical composition, the atmosphere is divided into two broad layers; the homosphere and the heterosphere. The homosphere extends up to the height of 56 mi. (90 km.) and is characterised by uniformity in chemical composition.It consists of three thermal layers, namely, the troposphere, the stratosphere, and the mesosphere. Each sub-layer is separated from the adjoining layer by a shallow transitional zone.
The heterosphere has heterogeneous chemical composition, with layered structure, of nitrogen, oxygen, helium, and hydrogen, respectively.
Generally, the atmosphere consists of five layers, namely, the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere.
The thickness of these layers is slightly different around the globe, and also varies with respect to temperature and season.
