What do the starfish grooves contain?

The grooves on a starfish, also known as sea stars, contain their tube feet, which are part of their water vascular system. These tube feet function in locomotion, feeding, and respiration. The grooves facilitate the extension and retraction of the tube feet, allowing the starfish to move and manipulate objects in their environment. Additionally, the tube feet are equipped with suction capabilities, helping them to cling to surfaces and capture prey.