Answer: Echinodermata.
- A Cnidaria
- B Mollusca
- C Echinodermata
- D Hemichordata
Correct answer: C. Echinodermata
Explanation: These are classic identifying features of Echinodermata (e.g., Asterias, starfish): radial symmetry in adults but bilateral in larvae, calcareous endoskeleton, water vascular system, and no specialized excretory organs.
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.