Question

Main function of pedicellariae in Asterias is ?
A) Digestion
B) Excretion
C) Respiration
D) Capture of prey and removal of debris

Answer 1

Star fish may be a triploblastic, centrosymmetric marine echinoderm that crawls on the ocean floor and preys upon molluscs. Its skin is extremely rough and the endoskeleton is formed of dermal ossicles. On the dorsal side the central disc carries a sieve plate or madreporite between the bases of the 2 arms through which water enters into the water system.

Complete answer:
The oral and aboral surfaces bear small, whitish, specialised jaw-like appendages called pedicellariae. These are found between the spines of the aboral surface, while they continue to be attached to the bases of the spines and also dwell the spaces between the spines on the oral surface.
These are used for cover, especially against small animals and larvae which will choose the body surface thereby keeping the body surface freed from debris. They'll also help in capturing small prey.
A pedicellaria (plural: pedicellariae) may be a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea).
Each pedicellaria is an effector organ with its own set of muscles, neuropils, and sensory receptors and is therefore capable of reflex responses to the environment. Pedicellariae are poorly understood but in some taxa, they're thought to stay the body surface beyond algae, encrusting organisms, and other debris in conjunction with the ciliated epidermis present altogether echinoderms.

Hence, the option D is the correct answer.

Note:
A pedicellaria (plural: pedicellariae) may be a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea).