Think of a deer in the woods that has just relieved itself by urinating. Number the steps to follow the nitrogen molecules in the urine as they go through the nitrogen cycle.

1. Step 1
3
The deer eats the plants and uses the nitrogen-containing proteins for cell growth.
2. Step 2
1
Plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.
3. Step 3
2
Ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. This is called nitrification.
4. Step 4
6
Some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere.
5. Step 5
5
Bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium.
6. Step 6
4
Nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification.