The selective expression of proteins like MSI60 and MSI31 in different layers of these objects likely help control substrate polymorphs. These objects’ resilience is partially due to a large, spring-like protein called lustrin A. These objects’ matrices consist of beta-chitin (“KY-tin”) sandwiched between beta-sheets of glycine and alanine-rich fibroin (-5[1])(“FY-broh-in”)-like proteins, all coated in a layer of aspartic (-5[1])acid-rich proteins. These objects incorporate a material in which hexagonal, (10[1])close-packed platelets form a regular “brick wall” structure. That biocomposite aragonite found in these objects (10[1])is responsible (-5[1])for their iridescent structural (10[1]-5[1])coloration. These objects consist (-5[1])of a periostracum, a prismatic layer, and a lustrous nacreous layer. (10[2]-5[3])They’re (-5[1])not (-5[1])trees, (-5[1])but these objects grow at (-5[1])their distal edges, leading to (-5[1])growth lines and characteristic (10[1])spiral shapes. For 10 points, (10[2])name these calcified (10[1])protective structures (10[1])formed by (10[1])mollusks like conchs. (10[2]) (10[11])■END■