Match the animal phyla/classes (Column X) with their defining set of characteristics (Column Y).

Column X	Column Y
A. Phylum Platyhelminthes	i. Bilateral symmetry, pseudocoelomate, complete digestive tract, often microscopic with a corona of cilia.
B. Phylum Annelida	ii. Radial symmetry (often pentamerous as adults), water vascular system, exclusively marine, deuterostomes.
C. Class Insecta	iii. Bilateral symmetry, acoelomate, triploblastic, usually with a flattened body and an incomplete digestive tract (if present).
D. Phylum Echinodermata	iv. Segmented body (metamerism) with a true coelom, chitinous cheetae (typically), closed circulatory system.
	v. Exoskeleton of chitin, three main body parts (head, thorax, abdomen), six legs, usually with wings in the adult stage.

Correct option is A

Answer: A — A–iii, B–iv, C–v, D–ii

Explanation

A (Platyhelminthes → iii): Flatworms are triploblastic, acoelomate, bilaterally symmetrical, usually dorsoventrally flattened with an incomplete gut (or no gut).

B (Annelida → iv): Annelids show metamerism (segmented bodies), possess a true coelom, chitinous chaetae (setae) in many groups, and a closed circulatory system.

C (Insecta → v): Insects have an exoskeleton of chitin, three main body regions (head, thorax, abdomen), six legs, and typically wings in the adult stage.

D (Echinodermata → ii): Echinoderms are marine deuterostomes with radial (often pentamerous) symmetry as adults and a water-vascular system.