What are the long-term carbon stores mentioned in the context of carbon dioxide decrease in the atmosphere?

The long-term carbon stores include limestone, coal, crude oil, and natural gas. These materials store carbon over geological time scales and play a significant role in the carbon cycle.

A strong answer should directly address the approved learning objective to describe limestone, coal, crude oil and natural gas as long-term carbon stores. This question belongs to How carbon dioxide decreased within The composition and evolution of the Earth's atmosphere, so the response should use that exact curriculum context rather than a generic statement. The answer is correct when it names the key idea, explains the link to limestone, and keeps the wording specific to AQA GCSE revision.