Question

Arrange the following in correct order based on increasing toxicity.

(a) Urea
(b) Uric acid
(c) Ammonia

• A. a-b-c
• B. b-a-c
• C. c-a-b
• D. c-b-a

Answer 1

The correct option is B b-a-c

Nitrogenous waste that is produced in the body needs to be excreted from the body as they are toxic to an organism. The waste is excreted in 3 forms, namely ammonia, uric acid, and urea. Ammonia is more water-soluble and most toxic. It requires less energy for excretion. Animals excreting nitrogenous waste in the form of ammonia are called as ammonotelic. Aquatic animals like protozoans, crustaceans, poriferans, fishes where water is not a constraint are ammonotelic. Urea requires comparatively more energy and is less toxic in nature. Animals excreting nitrogenous waste in the form of urea are called as ureotelic. Examples include cartilaginous fish, amphibians, mammals including humans. Uric acid is least soluble in water and is least toxic. However, it requires a large amount of energy. Examples include reptiles, birds.

Thus, the correct answer is 'b-a-c.'