If Echinoderms Are Radially Symmetrical,why Are They Considered Primitive Relatives

question 25

Multiple Choice

If echinoderms are radially symmetrical,why are they considered primitive relatives of cnidarians?

• A) Echinoderms branched from cnidarians but are considered more advanced because they also gave rise to chordates.
• B) The echinoderm larvae are originally bilaterally symmetrical but metamorphose into a radially symmetrical adult.
• C) Radial symmetry is maintained as a primitive state by all animals in the embryonic stage and can appear anywhere.
• D) Echinoderms are the most primitive of the deuterostomes and evolution begins in each group with radial symmetry.
• E) Echinoderms have a five-sided bilateral symmetry that just appears to be radial.