Binary fission is the primary method of reproduction for what type of organism?

Prokaryotes

Explanation:

Binary fission is an asexual form of reproduction commonly found in prokaryotes such as bacteria, and in some few cases seen in some few single-celled eukaryotes such as amoeba. Binary fission involves the division of a single parent cell into two identical daughter cells. It is the primary mode of reproduction in unicellular organisms like prokaryotes, which have no membrane-bound nucleus or other membrane-bound organelles. Bacteria reproduce asexually by binary fission.