What is a major reservoir for ammonia?

The major reservoir for Ammonia is the natural soil, where it is present in abundance.

Explanation:

In soil, ammonia is found in quite abundance, where it is changed into nitrate through a process commonly knows as Nitrification. In the nitrification process, first, nitrite is formed which is followed by its conversion into nitrate by a bacteria known as Nitrobacteria. Finally, this nitrate is consumed by the plants, which are then eaten up by the animals.

Explanation:

Morgan discovered a mutation that affected fly eye color. He observed that the mutation was inherited differently by male and female flies. Based on the inheritance pattern, Morgan concluded that the eye color gene must be located on the X chromosome.