Free Living Nitrogen Fixers — Prelims Questions

Which of the following free-living nitrogen-fixing bacteria is obligately aerobic and known for its high respiration rate to protect nitrogenase?

Which of the following is a free-living, anaerobic nitrogen-fixing bacterium commonly found in waterlogged soils?

Which specialized cell structure in filamentous cyanobacteria like *Nostoc* provides an anaerobic environment for nitrogen fixation?

Which of the following statements about free-living nitrogen fixers is INCORRECT?

The process of biological nitrogen fixation requires a significant amount of energy. Which molecule provides this energy?

Which of the following free-living nitrogen fixers would be most effective in acidic soils?