Question

Aquatic amphibians and chondrichthyes excrete ___ and ____, respectively.

• A. ammonia, urea
• B. urea, ammonia
• C. uric acid, urea
• D. ammonia, uric acid

Answer 1

The correct option is A

ammonia, urea

The correct option is A.

Explanation for correct option:

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