Given the question: You are presented with the question "What phylum do starfish belong to?" and the following answer choices: - fertile - animals - Echinoderm. - Mollusca. - Sponge. - Absorb light - Annelid. - a fish Now knowing that echinoderms have a unique water vascular system with tube feet and each starfish arm is lined with tube feet, choose the best answer.
The answer is:
Echinoderm.