Help me please please

I'm positive it's B. (Forgive me if I'm wrong.)

Explanation: Biologic isolation can lead to hybrids and it changes the genes. Take the albatross for example.

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.