Question

echinodermata knowledge check
what type of vascular system is unique to echinoderms?
tracheal system
closed circulatory system
open circulatory system
water vascular system

Explanation:

Echinoderms (like starfish) have a unique water vascular system used for locomotion, feeding, and respiration. Tracheal systems are in insects, closed circulatory in vertebrates (e.g., humans), open in arthropods/mollusks. So the unique one for echinoderms is water vascular system.

Answer:

D. Water vascular system