Final answer:
Echinoderms have tube feet as their appendages which are used for locomotion, feeding, and chemical sensations.
Step-by-step explanation:
Echinoderms are marine organisms that exhibit pentaradial symmetry as adults and have an endoskeleton made of calcareous ossicles. One common feature of echinoderms is the presence of appendages, which are called tube feet. These tube feet are used for locomotion, feeding, and chemical sensations.