Answer:
Volcanic activity releasing carbon into the atmosphere
Step-by-step explanation:
In the geosphere, carbon enters when the dead and decaying matter takes the form of fossil fuels. From the biosphere, the carbon enters into the geosphere through these sources. A carbon reservoir is maintained in the geosphere through these sources. The process of weathering, erosion, and volcanic eruption exposes the carbon content of the geosphere into the atmosphere. Volcanic eruptions upturn the carbon content of the geosphere and expose them.