Assertion : Pharyngeal nephridia play a role in the conservation of water in the earthworm.
Reason : They help the earthworm in keeping the skin moist for cutancous respiration.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

C

Explanation

Pharyngeal nephridia occur in three pairs of bunclies in the 4th, 5th and 6th segments lying on cach side of the alimentary canal. The ducts of the nephridia of the sixth segment open into the buccal cavity while the ducts from the nephridia bunches of the fourth and fifth segments open into the pharynx, These ducts carry excretory products from the pharyngeal nephridia into the gut. Enteronephric condition is an adaptation for the conservation of water which is absorbed by the inner lining of the alimentary canal.
Ectonephric nephridia discharge their contents directly to the outside which help the earthworm in keeping the skin moist for çutaneous respiration only. Integumentary nephridia are ectonephric nephridia while, pharyngeal and septal nephridia are enteronephric.