![Sea stars (starfish) endoskeleton on sand.](http://static.sciencelearn.org.nz/images/images/000/003/121/full/SEA_ITV_SeaStar_HardBodyPlates_cropped.jpg?1674169878)
Sea stars are invertebrates so they don’t have a backbone, but they do have a skeleton beneath their skin. This endoskeleton is made up of a complex network of hard bony plates made of calcium carbonate and held together by strong flexible tissues.
Acknowledgement: Suhailah J Nassar