Echinoderms have a unique water vascular system with tube feet.
Each starfish arm is lined with tube feet.
Each starfish arm contains part of the water vascular system.
Where does a starfish have its water vascular system?

[A] salt and water.
[B] Chlorophyll
[C] the environment
[D] in its arms
[E] on the rocks
[F] in its eyes
[G] Epidermis
[H] in the ocean