Echinoderms
A)are clearly related to cnidarians because of their radial symmetry.
B)may have evolved from a sessile ancestor.
C)probably evolved from pterobranch hemichordates.
D)do not show relationships to any other group of animals.

Question

Quizplus · Accepted Answer

Echinoderms share some similarities with sessile animals such as sea lilies and feather stars, and it is hypothesized that they evolved from a common ancestor with these animals.