Question

Radula is present in
A)Loligo
B)Mytilus
C)Pila
D)Unio

Answer 1

Hint: Radula is an anatomical structure generally used by mollusk for their feeding. Sometimes they are compared to as tongue. They are generally used for scraping or cutting of the food particles.

Complete answer:
The radula is an anatomical structure which is used by mollusks for feeding, occasionally compared to a tongue. It is a minutely toothed, chitinous ribbon, which is generally used for slicing or cutting food earlier than the food enters the oesophagus. The radula is exclusive to the molluscs, and is found in each class of mollusc apart from the bivalves, which in its place use cilia, waving filaments that carry minute organisms to the mouth.
In most of the further ancient lineages of gastropods, the radula is mainly used to graze, by splitting the diatoms and other microscopic algae off rock surfaces and other substrates.
Predatory marine snails including the Naticidae use the radula plus an acidic secretion to turn off through the shell of other molluscs. Other predatory marine snails like the Conidae, use a particular radular tooth as a poisoned harpoon.
A typical radula is composed of a number of bilaterally symmetrical self-like rows of teeth rooted in a radular membrane in the floor of their mouth cavity. A number of species have teeth that bend with the membrane as it moves over the odontophore, while in other species, the teeth are resolutely rooted in place, and the entire radular structure moves as one body.
1.Radular membrane: It is the elastic, delicate radular membrane might be a single tongue or may split into two.
2.Odontophore: The odontophore is the tongue of flesh underlying the radular membrane and it controls the organ's projection and return.
3.Flexibility: The radular teeth can usually bend in a sideways direction. In the patellogastropoda, even if the teeth lost this ability and became fixed.
4.Teeth: The radula comprises numerous, identical rows of teeth, fine, flat or spiny outgrowths. Frequently every tooth in a row along with its symmetric partner will encompass a unique morphology.
5.A rough organ with oblique teeth and present in the buccal cavity of a mollusca is generally called as radula. It is mainly used for feeding. It is mainly seen in Loligo. It is in the genus of squid. It is connected to the Cephalopoda class of mollusca.

Hence, the correct answer is option (A)

Note: Class bivalvia of mollusk family which includes the clams, oysters and mussels and numerous other families of the shell. The majority of them are filter feeders and they have no head or radula.