If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is

binary fission

Explanation:

Binary fission is the main type of reproduction of prokaryotic organisms. In binary fission, the prokaryotic cell first duplicates its DNA and then divides into two cells, each one receiving one complete DNA molecule. Since binary fission is a type of asexual reproduction, this process increases the prevalence of beneficial mutations in a bacterial population. Moreover, transduction refers to the process by which a virus transfers genetic information from one bacterium to another bacterium. Conjugation is also a sexual mode of transfer of DNA from a donor (F+) to a recipient (F−) bacterial cell by direct cell-to-cell contact. Finally, transformation refers to the transfer of genetic material by which bacteria take up exogenous DNA from the environment and integrate it in their genomes.

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.