Bacteria Cause Diseases in Humans When They

Bacteria cause diseases in humans when they

A) Carry genes that code for specific virulence factors that determine the type and extent of the illness.
B) Carry the same genes as the host organism causing them to be indistinguishable from the host cell.
C) Carry the genes of viruses causing them to be more harmful to humans.
D) Carry the genes of organisms like birds (bird flu) or pigs (swine flu) .
E) Carry genes that allow them to become symbiotes.