Final answer:
Sea stars, also known as starfish, have all six body wall layers in every part of their body. The ability to regenerate their arms is a unique trait that helps sea stars living in the intertidal zone.
Step-by-step explanation:
Sea stars, also known as starfish, have a unique body plan that consists of a central disk and multiple arms. Each arm of a sea star contains all six body wall layers, which include the skin, epidermis, dermis, coelomic epithelium, coelom, and muscles.
These different layers serve different functions, such as protection, movement, and digestion. The muscles in sea stars can do something that our muscles cannot - sea stars can regenerate their arms if they are damaged or lost.
This trait helps sea stars that live in the intertidal zone because they are exposed to harsh conditions, such as waves and predators. Being able to regenerate their arms allows them to recover from injuries and continue their survival in this challenging environment.