Question

Aquatic animals like fish excrete their wastes in gaseous form as

• A. Oxygen
• B. Hydrogen
• C. Ammonia
• D. Nitrogen

Answer 1

The correct option is C

Ammonia

The correct option is C.

Explanation for correct option:

1. Ammonia is direct waste which is produced as a byproduct of protein metabolism by all animals.
2. Because of its toxicity, many of the animals convert ammonia into less toxic form.
3. Any conversion of ammonia into its several other forms in animals requires expenditure of cellular energy (i.e. usage of ATP) to convert the ammonia to either form of nitrogenous waste. The excretory product in the humans is urea majorly.
4. Excess nitrogen is excreted from body. Nitrogenous wastes tends to form toxic ammonia, that raises the pH of body fluids.
5. The formation of ammonia also requires energy in the form of ATP and large quantities of water to dilute it out of a biological system.

Final answer: Aquatic animals like fish excrete their wastes in gaseous form as ammonia.