Concept:The Earth's atmosphere is divided into layers including the troposphere and thermosphere.
Explanation:The troposphere is the lowest layer, from the surface up to about 8–15 km.
The thermosphere is a higher layer above the mesosphere.
Both are parts of the atmosphere, along with stratosphere, mesosphere, and exosphere.
Thus, they belong to the atmosphere, not the lithosphere, hydrosphere, or biosphere.
Answer:Option A: Atmosphere