Answer:
A nitrogen atom can start its journey as part of an ammonium ion, for example. Through assimilation, a plant absorbs the ion and uses it to create an organic molecule. As part of a leaf, the organic molecule returns to the earth. Bacteria breakdown the leaf, which is then turned back to ammonium by ammonification. Through nitrification, the ammonium ion is transformed to nitrite by nitrifying bacteria.
Step-by-step explanation: