Answer: C. Maintains a balance of Earth's materials essential for all natural processes.
The geochemical cycle includes all the pathways of chemicals which takes place in the crust and surface of earth. Example: volcanic eruption. The elements like silica, iron etc comes out of the earth surface. The biogeochemical cycle includes all the natural cycles which takes place between living and non-living components of the ecosystem. Example: nitrogen cycle, phosphorous cycle, carbon cycle etc. These cycles maintains the balance of Earth's material essential for all natural processes such as photosynthesis, decomposition, sedimentation etc.