Assertion : Torison can be seen in ctenidium.
Reason : Ctenidium acts as the respiratory organ.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Ctenidium is a monopectinate gill situated on the right side of the branchial chamber. It helps in respiration by beating of cilia, thus creating water current. It is innervated by nerves from the left pleural and supra-intestinal ganglia. It basically indicates that it is an organ of the left side but has shifted to the right side during development (torsion).
Torsion or twisting is a development of gastropods, which rotates the visceropallium anticlockwise through out 180° from its initial position, so that mantle cavity with its pallial complex, is brought in front of the body in adult.
