Francine is developing a model of the carbon cycle, which involves the movement of carbon among various Earth systems. She begins by drawing the diagram shown below. In addition to the movement of carbon through Earth’s systems, Francine also wants her model to show how much carbon is stored in reservoirs or sinks. Which of these aspects of the carbon cycle could she add to her model to start building a more quantitative model? A. The process of photosynthesis moves carbon from the atmosphere to the biosphere.
B. About 550 gigatons of carbon is stored in plant biomass.
C. The ocean is the greatest carbon sink, storing about 38,000 gigatons of carbon per year.
D. Geologic processes such as eruptions move carbon from the geosphere to the atmosphere.