Polyps secrete calcium carbonate to form

hard skeletal structures that provide protection and support for the organism. This process is known as calcification, and it allows polyps to build stony structures such as coral reefs and shells. The calcium carbonate is deposited in layers, creating a solid framework that can withstand the harsh conditions of the marine environment. Through the secretion of calcium carbonate, polyps are able to create a durable and resilient habitat for themselves and other marine organisms.