Answer: Chitin.
- A Calcium carbonate
- B Silica granules
- C Chitin
- D Keratin fibres
Correct answer: C. Chitin
Explanation: The arthropod cuticle/exoskeleton is built chiefly of chitin, giving support and protection.
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.