* Biosphere: The biosphere encompasses all living things on Earth. While it's influenced by the other spheres (atmosphere, hydrosphere, etc.), it's not directly studied by any of the listed branches of science. Biology and ecology are the primary fields that study the biosphere.

* Exosphere: The exosphere is the outermost layer of Earth's atmosphere and is studied in astronomy and meteorology.

* Atmosphere: The atmosphere is the layer of gases surrounding Earth and is studied in meteorology.

* Hydrosphere: The hydrosphere includes all the water on Earth, including oceans, lakes, rivers, and groundwater. It's studied in oceanography.

Let me know if you'd like more explanation about any of the other spheres!