Question

Radula is found in which of the following species?
A. Pila sp.
B. Chiton sp.
C. Lamellidens sp.
D. Pinctada sp.

Answer 1

Hint:- Radula is a fringe of minute toothlike structures. It helps both in attaining the food by facilitating scraping of the particles from surfaces and in assimilating them before they enter the oesophagus.

Complete Answer:-
To know which species among the given options is associated with radula, it is important to identify the classification that the organisms belong to.

Options	Common Names	Class	Phylum
Pila sp.	Snails	Gastropod
Chiton sp.	Chitons	Polyplacophora	Mollusca
Lamellidens sp.	Mussels	Bivalvia
Pinctada sp.	Oysters	Bivalvia

Radula is a salient feature of molluscs, considered the analogue of tongue, specifically in gastropods. This unique structure of molluscs along with its supporting cartilage known as odontophore makes up the radula apparatus. The radula itself contains a stretch of 100-1000 backwardly curved tooth-like structures which slide over the odontophore with the help of retractor and protractor muscles to facilitate its overall movement necessary for it to function. New sections of teeth are constantly produced to replace the teeth worn away at the front. The shape and arrangement of the radular teeth are important in the identification of the species.
The purpose of the radula is to aid in scraping, grating, and swallowing of food particles into the digestive system of the molluscs.
The correct answer is Option A.

Note:- Radula is known to be present in all classes of molluscs except the Bivalvia which can thus make it confusing to choose between the options A and B. However, since the gastropods are the largest group of molluscs, the radula is most found in those organisms.