Question

Which one is the most poisonous excretory substance?
A. Uric acid
B. Urea
C. Ammonia
D. Hippuric acid

Answer 1

Hint: Excretion of waste from the body is the necessary process. The uric acid, urea and ammonia are the main excretory products. Accumulation of ammonia can be very dangerous for the body. Hippuric acid is the normal component of the urine. Mammals excrete urea. Birds excrete uric acid which is least toxic.

Complete answer:
Excretion is the physiological process. It involves the elimination of metabolic waste from the body. The products which excreted from the body are amino acids, urea, uric acid, carbon dioxide, water, and ammonia.

 Ammonia is the primary excretory product. Ammonia is derived from the food containing proteins. It is considered as the most toxic nitrogenous waste. The excretion of ammonia is done by the process of diffusion by most of the amphibians and aquatic animals. It is removed immediately from the body. It does not involve the kidney. The excretion of ammonia takes place with the help of water.

Molluscs and Echinoderms excrete the body wastes in the form of amino acids. Most of the mammals excrete nitrogenous waste as urea. It is less soluble in water and less toxic. Birds and reptiles excrete the body waste that includes nitrogenous waste as uric acid. Hippuric acid is the organic compound. It is formed by the combination of benzoic acid and glycine. It is normally found in urine.
From the above information we have found that ammonia is the most poisonous excretory substance.

Hence, the correct answer is option (C).

Note: Animals such as paramecium, amoeba and ascaris ammonia are excreted with the help of contractile vacuole. Hydra excretes from the general body surface. Kidney, ureter, urinary bladder and urethra are main excretory organs. Uric acid is the least toxic excretory product. Higher amounts of ammonia in the body can cause hyperammonemia which can lead to coma and death.