Explain why you usually find the onion cell nucleus at the edge rather than in the center of the cell.

The central vacuole occupies a good part of the middle of the cell,and the nucleus and cytoplasm are pushed to the sides!

Nitrifying bacterium, plural Nitrifying Bacteria, any of a small group of aerobic bacteria (family Nitrobacteraceae) that use inorganic chemicals as an energy source. They are microorganisms that are important in the nitrogen cycle as converters of soil ammonia to nitrates, compounds usable by plants.