Question

Ammonia is excretory material in

• A. Cartilaginous fishes
• B. Fresh water/bony fishes
• C. Whale
• D. Camel

Answer 1

The correct option is B Fresh water/bony fishes

Ammonia is excretory material in fresh water 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 'Fresh water/bony fishes'.