Question

The advantage of elimination of excretory waste in the form of urea by mammals and sharks is

• A. It raises the pH level of the blood.
• B. It sends signals from cells that produce it to other organs.
• C. It provides energy to some cells and tissues.
• D. It prevents ammonia from building up in the body.
• E. It eliminates water from the bloodstream.

Answer 1

Answer: (D)

It prevents ammonia from building up in the body.

The terrestrial mammals show ureotelic excretion due to the extreme toxicity of the ammonia that needs ample amount of water for dilution, In cartilaginous fishes like sharks, the build-up of ammonia disturbs the osmotic balance of the blood. So, they also convert the ammonia into the urea. So, conversion of ammonia into urea prevents its accumulation.

Hence, the correct answer is 'It prevents ammonia from building up in the body'