Question

Which ones are ammonotelic animals?

• A. Amphibian and reptiles
• B. Bony fishes and amphibian tadpoles
• C. Cartilaginous and bony fishes
• D. Amphibians and mammals

Answer 1

Answer: (B)

Bony fishes and amphibian tadpoles

Ammonia is excretory material in amphibian tadpoles and bony fishes because ammonia is a excretory product which is a very toxic substance to tissues and extremely soluble in water. It requires large amount of water to dissolve, about 0.5 L of water is needed per 1 g of nitrogen to maintain ammonia levels in the excretory fluid below the level in body fluids to prevent toxicity. So, this mode of excretion is desirable in aquatic animals. The process of excretion of ammonia is known as ammonotelic.

So, the correct answer is 'Bony fishes and amphibian tadpoles'.