Q.Match the following:

Each structure is matched with the group in which it is found:

• (a) Operculum — (viii) Osteichthyes: the bony gill cover protecting the gills.
• (b) Parapodia — (v) Annelida: lateral projections that help aquatic annelids such as Nereis swim.
• (c) Scales — (iv) Reptilia: the dry, cornified skin bears epidermal scales.
• (d) Comb plates — (i) Ctenophora: rows of fused cilia used for locomotion.
• (e) Radula — (ii) Mollusca: a file-like rasping organ in the mouth used for feeding.
• (f) Hairs — (vii) Mammalia: hair on the skin is a unique mammalian feature. …

Each of these structures is a characteristic feature that points to a particular group, so the match is made by recalling where each one is found.

• (a) Operculum — (viii) Osteichthyes. The bony fishes have their gills protected on each side by a bony cover called the operculum; the cartilaginous fishes lack it.
• (b) Parapodia — (v) Annelida. Aquatic annelids such as Nereis bear lateral projections called parapodia that assist in swimming.
• (c) Scales — (iv) Reptilia. Reptiles are covered by a dry, cornified skin bearing epidermal scales or scutes.
• (d) Comb plates — (i) Ctenophora. Ctenophores move using eight external rows of ciliated plates, the comb plates, made of fused cilia.
• (e) Radula — (ii) Mollusca. In molluscs the mouth carries a file-like rasping organ, the radula, used to scrape food.
• (f) Hairs — (vii) Mammalia. The presence of hair on the skin is one of the unique markers of mammals.
• (g) Choanocytes — (iii) Porifera. In sponges the spongocoel and canals are lined by flagellated collar cells called choanocytes. …

Method: Group-by-phylum-first, then match

Instead of matching each letter to its Roman numeral one pair at a time, first sort the eight groups in Column II by phylum/class, recall each phylum's single most defining structure, and only then read off which lettered structure belongs to it.

Sort Column II by phylum first:

• Ctenophora → its hallmark locomotory structure is the comb plate.
• Mollusca → its hallmark feeding structure is the radula.
• Porifera → its hallmark cell type is the choanocyte.
• Reptilia → its hallmark body covering is the scale.
• Annelida → its hallmark lateral structure (in aquatic forms) is the parapodium.
• Cyclostomata and Chondrichthyes → their shared hallmark respiratory openings are gill slits (uncovered by any operculum).
• Mammalia → its hallmark body covering is hair.
• Osteichthyes → its hallmark protective flap is the operculum, covering the gills that Chondrichthyes leave exposed.

With each phylum's single defining structure fixed in mind, the matching becomes a simple lookup rather than eight separate guesses: scan Column I (operculum, parapodia, scales, comb plates, radula, hairs, choanocytes, gill slits) and assign each term to the phylum whose hallmark it is — Operculum→Osteichthyes, Parapodia→Annelida, Scales→Reptilia, Comb plates→Ctenophora, Radula→Mollusca, Hairs→Mammalia, Choanocytes→Porifera, Gill slits→Cyclostomata and Chondrichthyes. …