Final answer:
The major reservoir for ammonia is urea in vertebrate animals. Uric acid is the major reservoir in birds, terrestrial arthropods, and reptiles. Other sources of ammonia include ammonification and its use in the production of fertilizers.
Step-by-step explanation:
The major reservoir for ammonia is urea, which is the byproduct of ammonia metabolism in vertebrate animals. Uric acid is the major byproduct of ammonia metabolism in birds, terrestrial arthropods, and reptiles. Another source of ammonia is ammonification, the process by which ammonia is released during the decomposition of nitrogen-containing organic compounds. Ammonia is also used in the production of fertilizers and plays a vital role in our global economy.