Question

In Mollusca, an eye is present over a stalk, called as
A. Osphradium
B. Ostracum
C. Ommatophore
D. Operculum

Answer 1

After Arthropoda, Mollusca is the second-largest phylum of invertebrate species. Molluscs or mollusks are known as the representatives. There is significant diversity amongst the body plan of the molluscs. But effectively there is a head, a foot and a visceral mass on the body.

Complete step by step answer:
In Mollusca, on a stumpy peduncle called the ommatophore, each eye is located. A loose skin fold, called the mantle, covers much of the body in Mollusca dorsally and encloses a large mantle cavity. The cavity of the mantle comprises the rectum, the genital duct, a male penis, and a small chemoreceptor called osphradium bipectinate. In Mollusca, a thick, plate-like operculum attached to the foot may tightly close the wide oval aperture or mouth of the shell.

Additional information: Mollusca (mollusks) are a broad animal phylum that includes, among others, snails, slugs, clams, squids, and octopi. Some are aquatic, many are freshwater, including some terrestrial snails and slugs. The name of the phylum refers (Mollis means "soft") to their soft, pulpy bodies. Most mollusks have a radula as well.
Hence, option C: Ommatophore is the correct answer.

Note: Ommatophore is an eyestalk, which is a protrusion that stretches the eye away from the body in Mollusca, including snails, giving the eye a better field of vision. Eyestalk is often referred to in Mollusca as ommatophore. It is a protrusion that spreads the eye away from the body and provides better vision for the area.