I think its C. , maybe ;)
Answer:
Embryological evidence
Explanation:
Deuterostomes is a group that includes echinoderms, hemichordates, and chordates. Although these animals exhibit a wide variety of body plans, they share a mouth secondarily formed during embryo development, which it is believed to be an evolutionarily derived character present between a common ancestor and all its descendants (i.e., a synapomorphy). This oral cavity is formed by the invagination of the ectoderm layer opposite to the blastopore of the gastrula.
So that the starfishes surface doesn't get covered in encrusting organisms such as planktons or parasites.
Answer:
D, amino acids is the answer.
