Sore throat is a symptom, not a disease. In each case, there was a different cause that dictated a different treatment. The scratchy throat probably was a mechanical problem caused by dry, heated winter air and aggravated by my friend's tendency to breathe through her mouth when she sleeps.
Biogeochemistry includes the history of the great carbon reservoirs in the crust of the Earth, like limestone rocks and the coal deposits, as well as the distribution of nitrate and phosphate in the ocean.
Figure 1. illustrates the annual movement of tens of billions of carbon dioxide between the atmosphere, water, and soil which are the major reservoirs, or sinks of CO2 - and under other conditions, a source for carbon dioxide.