A Soil Sample Taken Shortly After a Large Chemical Spill

A soil sample taken shortly after a large chemical spill has occurred reveals only a few living bacteria.Six months later,a second sample from the same site reveals only a single bacterial species,which is present in high numbers.What may have caused this change?

A) This bacterial species was most likely left at the site by the original sampling equipment.
B) Animals passing through the area most likely deposited fecal matter full of microbiota.
C) The bacterial species found in high numbers contains at least one gene that provides a competitive advantage.
D) The single bacterial species must have been within the gut of a shelter species.