What sedimentary rock is made underwater from the shells of animals?

The sedimentary rock made underwater from the shells of animals is limestone.

Here's why:

* Formation: Limestone forms primarily from the accumulation of the calcium carbonate (CaCO3) shells and skeletons of marine organisms like corals, mollusks, foraminifera, and algae.

* Process: Over time, these shells and skeletons pile up on the ocean floor, compact, and cement together, eventually forming limestone.

* Other Sources: While most limestone is biogenic (formed from living organisms), some limestone can form through chemical precipitation or the accumulation of other carbonate materials.

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