Question

Primary function of enteronephric nephridia of Pheretima:

• A. Osmoregulation
• B. Excretion of nitrogenous waste
• C. Respiration
• D. Locomotion

Answer 1

The Correct Option is B

The primary function of enteronephric nephridia in Pheretima, which is a genus of earthworm, is the excretion of nitrogenous waste. Let's explore why this is the case:

1. Understanding Nephridia: Nephridia are excretory organs in annelids like earthworms. They serve a function similar to kidneys in vertebrates, aiding in the removal of waste from the animal's body.
2. Types of Nephridia: In earthworms, there are different types of nephridia based on their location and function, including enteronephric nephridia and exonephric nephridia. Enteronephric nephridia release waste into the gut.
3. Function of Nephridia: The primary role of enteronephric nephridia is to regulate the balance of water and excrete nitrogenous waste (such as ammonia and urea) from the body. These wastes are by-products of protein metabolism.
4. Excretion Process: The excretion of nitrogenous waste is vital as it helps in maintaining the internal chemical balance of the organism. This process involves filtering the waste out of the blood or body fluids, which then passes into the intestine via the gut, and ultimately expelled through the anus.
5. Ruling Out Other Options:
   • Osmoregulation: While nephridia do play a role in osmoregulation, the primary function specified for enteronephric nephridia in Pheretima is more specific to excretion.
   • Respiration: This is not the function of enteronephric nephridia. Respiration in earthworms occurs through their moist skin.
   • Locomotion: Earthworm locomotion is facilitated by their muscles and setae (bristles), not by nephridia.
6. Conclusion: The correct answer to the question, based on the explanation, is Excretion of nitrogenous waste.