Ques. 1AIPMT 2001
In Hydra, waste material of food digestion and nitrogenous waste material are removed respectively from
- mouth and mouth
- body wall and body wall
- mouth and body wall
- mouth and tentacles
Answer
(3) mouth and body wall
Solution
As per NCERT, cnidarians have a central gastro-vascular cavity with a single opening, the mouth on hypostome; digestion is extracellular and intracellular.
∵ There is no anus, the undigested food (waste of digestion) is thrown out through the mouth.
Hydra is ammonotelic; it has no excretory organs, and ammonia diffuses out through the general body surface (body wall) into the surrounding water.
∴ Waste of digestion → mouth; nitrogenous waste → body wall.
Answer: (3)