Answer:
Horizontal
Step-by-step explanation:
Horizontal gene transfer may be defined as the transfer of the genetic material from the parents to their offspring. Three main methods of horizontal gene transfer are conjugation, transformation and transduction.
The transfer of plasmid among the members of bacterial community mainly occur by the horizontal gene transfer. This transfer of genetic material allows the bacteria to withstand at extreme conditions, confer antiobiotic resistance and increase their chance of survival in the environment.
Thus, the answer is horizontal gene transfer.