Question

in the carbon cycle, co₂ is mainly stored in ___.

• rocks, such as limestone
• the atmosphere
• living organisms

Explanation:

In the carbon cycle, the largest reservoir of carbon (in the form related to \( \text{CO}_2 \) storage, like carbonate rocks) is in rocks such as limestone (calcium carbonate - based rocks store a vast amount of carbon over geological timescales). The atmosphere has a relatively small amount of \( \text{CO}_2 \) compared to rock reservoirs, and living organisms also store carbon but not as the main long - term or large - scale storage for \( \text{CO}_2 \) - related carbon in the cycle.

Answer:

A. rocks, such as limestone