Initiation, elongation, and then termination
Your answer would be A. Phosphorus
Eukaryotic cells are cells that have a nuclear envelope, cytoplasmic organelles, and a cytoskeleton.
Prokaryotic cells are cells lacking a nuclear envelope, cytoplasmic organelles, and a cytoskeleton (primarily bacteria).
Also Eukaryotic cells have a nucleus in which the genetic material is separated from the cytoplasm.
Also Prokaryotic cells are generally smaller and simpler than eukaryotic cells; in addition to the absence of a nucleus, their genomes are less complex and they do not contain cytoplasmic organelles or a cytoskeleton
So the correct answer would be B.
Hope I helped.
I dont think it is symbiotic, it is parasitic relationship. They get blood supply of human and dont give anything useful to humans