Limestone is common on Earth because life produces it en masse: the rock forms when shells and skeletons of ocean creatures, especially from coral reefs, pile up on the seafloor as the organisms die.

石灰岩在地球上很常见，因为生命会大量产生它：当海洋生物（尤其是珊瑚礁）的贝壳和骨骼在生物死亡时堆积在海底时，岩石就形成了。