Here's why:
* Chemically: Limestone can form from the precipitation of calcium carbonate (CaCO3) from water, often in marine environments. This happens when water becomes supersaturated with calcium carbonate, leading to the formation of calcite crystals that accumulate and harden into limestone.
* Organically: Limestone can also form from the accumulation and cementation of the remains of marine organisms, such as shells, corals, and algae. These organisms extract calcium carbonate from the water to build their skeletons and shells. After they die, their skeletal fragments accumulate on the seafloor, eventually being compressed and cemented together to form limestone.
So, while the formation processes differ, the end product, limestone, is essentially the same.
