Molecular biology is a field of biology that looks at the molecular machinery of life. The field was founded in the early 1930s, though the phrase was only used in 1938 and the field didn't take off until the late 50s and early 60s. Since then, progress in the field has been massive.
The Ionosphere and the Exosphere (minor layers) are parts of the Thermosphere (major layer). The ionosphere is part of the theremosphere.
Earths Atmosphere Layers. The Earths atmosphere layers are similar to the layers in the interior of the Earth. There are four major layers of atmosphere above the Earth that are separated by temperature. Each layer of the layers are separated by an increasing or decreasing temperature of the gases in the layer. The tropopause, stratopause, mesopause are areas where two atmosphere layers gradually transition from one layer into another layer.