Final answer:
Prokaryotes primarily exchange genetic information through conjugation, a process where DNA is transferred between two cells via a cytoplasmic bridge formed by a conjugation pilus, which results in increased genetic variation among prokaryotes.
Step-by-step explanation:
Prokaryotes can swap genetic information primarily through a process called conjugation, which is the correct answer to the question. In conjugation, DNA is transferred between two prokaryotic cells via a cytoplasmic bridge formed as a result of a conjugation pilus, or sex pilus, bringing the cells into contact. This method of genetic transfer allows for increased genetic variation within prokaryotic populations. Besides conjugation, other mechanisms through which prokaryotes can exchange DNA include transformation, where DNA is taken up from the environment, and transduction, where DNA is transferred via bacteriophages (viruses that infect bacteria).