Step 1: Understanding the Concept
The ornithine cycle takes place in the liver of ureotelic animals.
Step 2: Product
Ammonia from amino acid breakdown combines with carbon dioxide in this cycle to form urea.
Urea is much less toxic than ammonia and dissolves readily in water.
Step 3: Other options
Uric acid is almost insoluble and not made in this cycle, ammonia is highly toxic, and amino acids are not wastes.
Step 4: Conclusion
The waste described is urea.
Final Answer:
The waste is urea.
\[ \boxed{\text{(A) }\text{Urea}} \]