Question

The Pluteus larva of Echinodermata belongs to the class of
A. Holothuroidea
B. Crinoidea
C. Echinoidea
D. Asteroidea

Answer 1

Hint:It is the only larval stage, and the larva, called the pluteus, has a thin, wart-like bud that develops into an adult when the pluteus tissue disintegrates.

Complete answer:
Organisms belonging to the phylum Echinodermata are exclusively marine and are distinguished by the presence of spiny skin. They show a range of body types. The general form of the echinoderm may be that of a star with arms extended from the central disc or with branches and feathered arms extended from the body frequently attached to a stalk, or it may be circular or cylindrical. Echinoderms are classified into 21 classes, primarily based on variations in skeletal structures.

Holothuroidea is a class of echinodermata, also known as sea cucumber. Holothuroidea class displays two larval stages, namely auricularia and doliolaria larva.Crinoid, also called sea lilies, of the class Crinoidea(phylum Echinodermata) typically has a rather cup-shaped body and five or six flexible and active arms. Pentactula is the basic larval stage of Crinoidea, but it passes from inside the egg. There are one or two larval stages of the sea lilies. Sea star, also known as starfish, in the class Asteroidea Possesses rays, or arms, circling the indistinct central disc. There are three larval stages in the development of Asteroidea To the adult stage.

Echinoids are also known as sea urchins. They are distinguished by a globulous body and a radial pattern of organs, seen by five pore bands extending from the mouth to the anus around the test (internal skeleton). There is a single larval stage in the echinoid known as Echinopluteus, which is bilaterally symmetrical. The larva has an oval body with long paired ciliated arms protected by calcareous skeletal rods.

Thus, the correct answer is C i.e., Echinoidea.

Note:There are two larval stages in holothuroidea, asteroids and ophiuroids. Echinoids have one larval stage, the echinopluteus, which is also the stage of settlement.