* Geosphere: Paleontologists study fossils which are preserved remains or traces of ancient organisms. These fossils are found in rocks, which are part of the Earth's crust and therefore the Geosphere. They use geological knowledge to understand the age and environment in which these fossils were formed.
* Biosphere: The Biosphere encompasses all living things on Earth. Paleontologists study the history of life on Earth, including extinct organisms and their relationships to modern species. They contribute to our understanding of how life has evolved and changed over time.
Therefore, while their research may involve other Earth systems like the Hydrosphere (water) and Atmosphere, the Geosphere and Biosphere are the two most directly related to their work.
