Regeneration is the process in which an organism can regenerate its body parts e.g. sea star can regenerate its lost arm. Binary fission: Binary fission means "division into two". It is the simplest and most common method of asexual reproduction. It occurs in prokaryotes (bacteria). Many unicellular eukaryotes e.g. protozoa and some invertebrates. Correct Answer Regeneration is the process in which an organism can regenerate its body parts e.g. sea star can regenerate its lost arm. Binary fission: Binary fission means "division into two". It is the simplest and most common method of asexual reproduction. It occurs in prokaryotes (bacteria). Many unicellular eukaryotes e.g. protozoa and some invertebrates.