Binary Fission means "division into two" . It is the simplest and the most common method of asexual reproduction .It occurs in prokaryotes e.g bacteria, many unicellular eukaryotes e.g protozoa and some invertebrates. During Binary Fission in bacteria, the bacteria split in two, so one bacterium becomes two bacteria. This always leads to daughter cells, and the offspring will be identical to the parent. In other words the single cell doubles its DNA and divides into two cells.