Animal Kingdom Question 463
Question: Assertion : ‘Chain-saw movement’ is found in mollusca. Reason : ‘Chain saw movement’ helps in feeding or ingestion of food.
Options:
A) If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B) If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C) If the assertion is true but the reason is false
D) If both the assertion and reason are false
Show Answer
Answer:
Correct Answer: B
Solution:
Radula of Pila is moved forward and backward on the odontophore for rasping food particles.
Movements, called chain-saw movements ((Huxley), are brought about by protractor and retractor muscles, the radula can even be protruded from mouth.
Food is taken into the buccal cavity by the ?chain-saw? movements of radula.
By the action of sphincter and protractor muscles of the buccal mass, the two jaws move upto the mouth opening and cut up leaves of aquatic plants.
Meanwhile the radula is also brought forward, the pieces of leaves caught by its teeth are thrown backward into the buccal cavity.
Thus, the food is cut and masticated inside the buccal cavity.
The chain-saw movements of radula are limited in Pila in comparison to the molluscs.
BETA
