What make up starfish endoskeleton?

Starfish don't have an endoskeleton in the same way that vertebrates do (like humans). Instead, they have a calcium carbonate skeleton that is part of their exoskeleton, meaning it's on the outside of their body.

Here's how it works:

* Ossicles: The starfish's skeleton is made up of tiny, interlocking plates called ossicles. These ossicles are made of calcium carbonate and are joined together by a flexible, leathery skin.

* Flexibility: This arrangement allows for a surprising amount of flexibility, enabling starfish to squeeze into tight spaces and move in a variety of ways.

* Protection: The ossicles also provide protection against predators.

* Shape and Structure: The ossicles are arranged in a pattern that gives the starfish its distinctive shape and structure.

So, while it's not technically an endoskeleton, the calcium carbonate ossicles of a starfish provide crucial structural support and protection, playing a vital role in their survival.