I think it's C. Because photosynthesis is when plants release oxygen so that can't be it. And cellular respiration is when animals/humans release carbon dioxide into the world. So no and burning just can't be it because it destroys everything. So C. Also when decomposition happeneds plants and animals are turned into fossil fuels
Biogeography is the study of geographical distribution of fossils, various species (plants and animals) and ecosystems throughout geological time and space