If you were trying to identify an unknown adult animal that must be either an echinoderm or chordate, which morphological feature (s) would guarantee that your organism was an echinoderm rather than a chordate.

The radial symmetry and mesodermal skeleton in echinodems

Bilateral symmetry and internal skeleton of chordates

Explanation:

The echinoderms have radial symmetry and their skeleton is mesodermal made up of calcites known as ossicles while the chordates have bilateral symmetry and their internal skeleton is made up of bones and cartilages.