If you wanted to study climate change which fossil would be most useful a fossil of an organism that is?

To study climate change, a fossil of an organism that is sensitive to temperature and environmental conditions, such as a coral or foraminifera, would be most useful. These organisms can provide insights into past ocean temperatures and conditions, as their growth patterns and chemical compositions reflect changes in climate over time. Analyzing their fossils can help reconstruct historical climate data and understand the impacts of climate change on marine ecosystems.