Question

Sol. Key concept: Characteristic tissues and organs of major animal phyla.

V–(iii): Cnidarians have gelatinous mesoglea between the epidermis and gastrodermis. It is especially conspicuous in jellyfish.

W–(i): Nematodes have a commonly syncytial epidermis or hypodermis beneath the cuticle; a syncytium contains many nuclei in a shared cytoplasm.

X–(v): Parapodia are paired lateral appendages of polychaete annelids such as Nereis. They help in movement and may also assist gas exchange.

Y–(ii): In acoelomate flatworms (Platyhelminthes), parenchyma occupies the space between the body wall and internal organs.

Z–(iv): The radula is a rasping feeding structure characteristic of most molluscs, though it is absent in bivalves. Hence V–iii, W–i, X–v, Y–ii, Z–iv: option a.