Answer: Echinodermata.
- A Echinodermata
- B the phylum Arthropoda
- C only Mollusca members
- D a group called Aves
Correct answer: A. Echinodermata
Explanation: Echinoderms possess a unique water vascular system.
Moving across the animal phyla, body organisation becomes progressively more complex: from no symmetry and cellular organisation (Porifera) through radial/diploblastic (Cnidaria), bilateral/acoelomate (Platyhelminthes), pseudocoelomate (Nematoda), to a true coelom with full organ systems (Annelida and beyond).
Concept context
Phylum-level classification of the animal kingdom from Porifera to Chordata, based on body symmetry, coelom, and segmentation. One of the most example-heavy chapters for NEET.