1
Primary function of enteronephric nephridia of Pheretima:
- Excretion of nitrogenous waste
- Locomotion
- Osmoregulation
- Respiration
Answer
(3) Osmoregulation
Solution
In Pheretima the nephridia (septal and pharyngeal) open into the alimentary canal, so they are called enteronephric nephridia.
⇒ As per NCERT, nephridia of earthworm help to remove nitrogenous wastes and maintain a fluid and ionic balance.
∵ Being enteronephric, they pour water into the gut, which is reabsorbed there, so water is conserved.
∴ Their primary function is osmoregulation.
Answer: (3)
AIPMT 2000