Pick the INCORRECT statement regarding to the excretory products:

Urea is the most toxic form and requires large amount of water for its elimination.

The correct answer is Option (3)- Urea is the most toxic form and requires large amount of water for its elimination.

Animals accumulate ammonia, urea, uric acid, carbon dioxide, water and ions like Na + , K+ , Cl– , phosphate, sulphate, etc., either by metabolic activities or by other means like excess ingestion. These substances have to be removed totally or partially. Ammonia, urea and uric acid are the major forms of nitrogenous wastes excreted by the animals. Ammonia is the most toxic form and requires large amount of water for its elimination, whereas uric acid, being the least toxic, can be removed with a minimum loss of water.

The process of excreting ammonia is Ammonotelism. Many bony fishes, aquatic amphibians and aquatic insects are ammonotelic in nature.