Question

question 30
the echinoderms are most closely related to the ______.
○ arthropods
○ mollusks
○ flatworms
○ chordates

Explanation:

Echinoderms and chordates are both deuterostomes. In the animal classification, during embryonic development, deuterostomes share certain key characteristics such as the formation of the anus before the mouth. Arthropods, mollusks, and flatworms are protostomes, which have a different pattern of embryonic development where the mouth forms before the anus.

Answer:

chordates