What process do bacteria primarily use for reproduction?

Bacteria primarily reproduce through binary fission, which is an asexual process. In binary fission, a single bacterial cell grows and then divides into two identical daughter cells. This method allows for rapid population growth under favorable conditions, as it can occur in as little as 20 minutes in some bacterial species.

During binary fission, the bacterium undergoes DNA replication followed by the elongation of the cell, which ultimately leads to the division of the cell membrane and the cytoplasm, resulting in two genetically identical cells. This process is efficient and does not require the exchange of genetic material, which is typical of sexual reproduction methods like meiosis or conjugation.

In contrast, meiosis is a type of division that reduces the chromosome number by half typically used in sexual reproduction, while conjugation involves the transfer of genetic material between bacteria, enhancing genetic diversity but not directly leading to reproduction. Bud formation is a process more commonly associated with yeast and some protozoa, rather than bacteria. Therefore, binary fission is recognized as the primary reproductive method for bacteria, making it the correct answer.