Which has prokaryotic cells? 1. onion root 2. cow's liver 3. human blood 4. e. coli

E.coli consists of prokaryotic cells. A prokaryotic cell is a single-celled organism, generally a bacteria. E. coli is a bacteria that lives in the intestines of people and animals.

Explanation:

Prokaryotic cells are cells that don't have a real nucleus or most different cell organelles. Organisms that have being cells are living thing and known as prokaryotes. Microorganism and archaea are prokaryotes.

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.

the supermassive black hole is in the middle of the galaxy.