Terrestrial organisms must conserve water. The least amount of water is lost with the excretion of which nitrogenous waste product?

A. Uric acid

B. Urea

C. Carbon dioxide

D. Ammonia

A. Uric acid

Explanation:

Most water is conserved in the body of an organism which excretes uric acid as urinary waste or in short we can say that least water is lost from the body of organisms which excrete uric acid. Based on the habitat and niche, body of various organisms are adapted to produce either ammonia, urea or uric acid as waste products. Among ammonia, urea and uric acid, uric acid is least toxic and also requires very less water in order to get excreted out of the body.

Birds spend most of the time in sky flying high, in such scenario they do not get enough excess to water because within sky there are no water resources so it is their utmost necessity to conserve water in the body. They get access to water resources only when they come back to land which is not a regular practice for them. This is the reason why birds excrete uric acid as nitrogenous waste product.