Answer: Radula.
- A Radula
- B Mantle
- C Spicule
- D Madreporite
Correct answer: A. Radula
Explanation: The radula is a file-like rasping organ found in the mouth of most molluscs, used to scrape food. The mantle covers the visceral hump.
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.