Biological nitrogen fixation is carried out exclusively by which organisms?

1. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia. 2. It is carried out exclusively by prokaryotes, such as soil bacteria or cyanobacteria. 3. The legume itself does not fix nitrogen, it houses the bacteria that do, which is why legume root cells are the trap here. 4. Mycorrhizal fungi are eukaryotes and their role is mineral uptake, chiefly phosphate, rather than nitrogen fixation. 5. Soil invertebrates contribute to soil structure but take no part in fixation. 6. The most important source of this fixation is the symbiotic interaction between soil bacteria and legume plants. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 31 "Soil and Plant Nutrition", section 31.3 Nutritional Adaptations of Plants_