Matthias Schleiden and Theodor Schwann made which contribution to science? A. Discovered that new organisms do not spontaneously arrive in suitable conditions, but must be brought there.
B. Discovered the process plants use for energy, photosynthesis.
C. Discovered a basic principle of chemistry, that all matter is composed of atoms.
D. Discovered a basic principle of biology, that all plants and animals are made of cells.

D. Discovered a basic principle of biology, that all plants and animals are made of cells.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 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 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.