Question

Which of the following is not a correct pair?
A. Trochophore-Annelid
B. Bipinnaria-Echinodermata
C. Tornaria-Arthropoda
D. Planula-Coelenterata

Answer 1

An arthropod is an invertebrate animal that has an exoskeleton and a segmented body.
They also contain paired jointed appendages. Arthropods form the phylum Arthropoda which includes insects, arachnids, myriapods, and crustaceans. The term Arthropoda as originally proposed refers to a proposed grouping of Arthropods and the phylum Onychophora.

Complete answer:
A trochophore is a small, translucent, free-swimming planktonic marine larva with several bands of cilia.
By moving cilia, they control the direction of their movement. It is a characteristic feature of marine annelids and most groups of mollusks. A bipinnaria is a primary stage in the larval development that occurs in most starfish. And it is usually followed by a brachiolaria stage. Starfish that brood when they're young lack the bipinnaria stage with the eggs that directly develop into miniature adults (Echinodermata). A tornaria is the planktonic larvae of some species of Hemichordata such as acorn worms. It is an oval-shaped, transparent larva. The diameter of the body is about 3 mm. It has an apical plate, which is a thickened region provided by a tuft of cilia and a pair of eyespots (and not Arthropoda).
A planula is a free-swimming, flattened, ciliated, bilaterally symmetrical larval form of various cnidarian species and is also seen in some species of Ctenophora.
So, the correct option is option C, i.e., Torneria-Arthropoda.

Note: The body plan of hemichordates is characterized by a muscular organization. The anteroposterior axis is further divided into three parts:
1. The anterior prosome
2. The intermediate mesosome
3. The posterior metasome.
The body of acorn worms is worm-shaped and divided into an anterior proboscis, an intermediate collar, and a posterior trunk.