Question

what are the two main reservoirs for carbon dioxide? options: atmosphere, fossil fuels; calcium carbonate, ocean; ocean, atmosphere; ocean, fossil fuels.

Explanation:

To determine the two main reservoirs for carbon dioxide, we analyze the carbon cycle. The ocean dissolves a large amount of CO₂, and the atmosphere contains gaseous CO₂. Among the options, "Ocean, atmosphere" correctly identifies these two primary reservoirs. Other options include components (like fossil fuels, calcium carbonate) that are not the main direct reservoirs for CO₂ in the context of this question.

Answer:

Ocean, atmosphere