Hydra removes undigested food by

Explanation

Hydra is a type of aquatic animal that feeds on small aquatic animals and plants. When it feeds, it takes in food into its body cavity where digestion takes place. After digestion, undigested food needs to be removed from the body. The question is asking how Hydra removes undigested food. Option A suggests that Hydra removes undigested food by passing it through the anus, which is incorrect. Hydra does not have an anus, which is an opening at the end of the digestive tract through which solid waste is eliminated from the body. Option B suggests that Hydra removes undigested food by passing it through the mass, which is the correct answer. Hydra does not have a specialized structure for waste elimination. Instead, it eliminates undigested food by passing it out through the same opening through which it took in food. This opening is called the mouth or the mass. Option C suggests that Hydra removes undigested food by means of a contractile vacuole, which is incorrect. Contractile vacuoles are organelles found in some unicellular organisms that pump excess water out of the cell. Option D suggests that Hydra removes undigested food by egering it through the body surface, which is incorrect. Hydra does not have a specialized structure for waste elimination through the body surface. Option E suggests that Hydra removes undigested food by passing it through the nose, which is incorrect. Hydra does not have a nose or any structure that can be called a nose. In summary, the correct answer to the question is option B, Hydra removes undigested food by passing it through the mouth or the mass.