Question

In Hydra, egestion of undigested food and excretion of nitrogenous waste occurs through

• A. mouth and anus, respectively
• B. mouth and body surface, respectively
• C. anus and body wall, respectively
• D. mouth and tentacles, respectively

Answer 1

The correct option is B mouth and body surface, respectively

Hydra has an incomplete digestive system where there is only one opening that is the mouth. There is no anus. The food enters and the undigested waste exits the body through the same opening of the mouth. Hydra has no organ for excretion of nitrogenous wastes. It diffuses out into the surroundings through the surface of the body. It uses its tentacles for feeding and not for egestion or excretion.