Some animals excrete nitrogen containing wastes as urea in urine. others excrete uric acid in the form of a thick paste. in which type of environment does the excretion of uric acid provide the greatest advantage

Uric acid would produce the most advantages in a desert climate. Uric acid is water insoluble, therefore it doesn't need water to be produced. It has the advantages of reducing water loss and, hence, reducing the need for water. Overall, if a bird or reptile was in a desert climate, or somewhere with little water, it would probably do better. Hope this helps!