Biology

The correct answer is: B.Ocean, atmosphere.

Explanation:

The two main reservoirs for carbon dioxide (CO₂) are:

1.Atmosphere: The atmosphere holds CO₂ in its gaseous form. This is the immediate source of CO₂ that interacts with living organisms, plants (via photosynthesis), and the oceans.

2.Ocean: The oceans are the largest carbon sink, absorbing and storing large amounts of CO₂. Through processes such as physical absorption (via diffusion) and biological processes (like photosynthesis by marine plants), the oceans play a crucial role in regulating atmospheric CO₂ levels.

Why the other options are incorrect:

A.Ocean, fossil fuels: Fossil fuels (coal, oil, and natural gas) store carbon in a solid or liquid form over...