Question

Buccal cavity of Molluscs contains a special rasping organ.What is it known as?
A. Tongue
B. Dental plate
C. Radula
D. Mantle plate

Answer 1

Mollusca is one of the most diverse animal groups on the planet, with at least 50,000 (and possibly about 200,000) living species. It includes snails, octopuses, squid, clams, scallops, oysters and chitons, which are familiar species.

Complete Answer:
- Molluscs are a clade of species that typically have a head and foot area, all with soft bodies. Their bodies are also covered, as in the shells of snails and clams or the plates of chitons, by a rigid exoskeleton. The body has a head, a foot and a visceral mass.
- All of this is filled with a mantle that normally secretes the shell (also known as a pallium). The mantle is secondarily lost in some species, including slugs and octopuses, while it is used for other tasks, such as breathing, in others.
- The buccal cavity comprises a radula (lost in bivalves) at the front of the mollusc, a ribbon of teeth supported by an odontophore, a muscular structure.
- Typically, the radula is used for feeding. It is a tiny structure made of chitin, like a small chainsaw. In locomotion, the ventral foot is working. By using muscular waves and/or cilia in conjunction with mucus, this foot propels the mollusc.
- In the posterior cavity (pallial cavity) or in the posterolateral groove around the foot of each group, at least one or more pairs of gills (called ctenidia) lie. A pair of sensory (smelling) osphradia is typically present in the pallial cavity and is an opening for the kidneys, gonads and anus.

The correct Answer is option (C) Radula.

Note: The introduction of various feeding patterns seems to have had a significant impact on the evolution of molluscs. One of the main characteristics of the group's radiation is the transition from grazing to other types of food acquisition. The earliest molluscs grazed on encrusting animals and detritus on the basis of our present understanding of relationships.