Options are: [I] h2o; [II] insects; [III] sea urchins; [IV] bushes; [V] Most plants; [VI] Conifers; [VII] orchids; [VIII] humans;

Fact 1: Echinoderms have a unique water vascular system with tube feet. Fact 2: Starfish and sea urchins are also echinoderms. Given the two facts above, what have a unique water vascular system with tube feet?
Answer:
[III]