Question

Which region of earthworm is called a forest of nephritides?
A. Clitellar region
B. Pharyngeal region
C. Typhlosole region
D. Intestinal region

Answer 1

Hint: Nephridia are coiled tubular ducts like organs, filter and remove waste from the body of earthworm. These are grouped in pairs through the segments of the worm body. Nephridia filters nitrogen from the cluster of capillaries it is surrounded with. The ends of all pharyngeal nephridia combine and form waste ducts of large size that dumps into the buccal chamber and pharynx which is a tube which extends from the pharynx to the mouth.

Complete answer:
In the body of earthworm there are numerous nephridia from seventh to last segment as nephridia remain attached with the body walls of the earthworm. There are about 200-250 integumentary nephridia which are segments of the clitellar region where the number is two thousand to twenty five hundred in each segment. Their nephridia are small sized, without opening into the coelom and without a nephrostome. Therefore, this region of earthworm is a forest of nephridia as the name suggests it has numerous nephridia in the clitellar region. Hence, the correct answer is A. Clitellar region. These nephridia serve the channel as it let nitrogenous waste from inside from the worm to the outside soil and help in fertility of soil as this nitrogenous waste is good for the soil.

Note:
Pharyngeal region extends to the fourth segment and has a pharyngeal bulb and helps in mixing of mucus and grinding of fruit and then passes the food to other parts. Typhlosole is the internal fold of the intestine and runs along the length of the body of earthworm and increases absorption of the area of the inner surface.