According to this figure, what can directly use atmospheric N₂?

Question

Quizplus · Accepted Answer

Only nitrogen-fixing bacteria, such as those in the genus Rhizobium or Azotobacter, have the ability to convert atmospheric N2 into a form usable by plants, such as ammonium (NH4+). Plant roots cannot directly use atmospheric N2 without the help of nitrogen-fixing bacteria. Ammonifying bacteria and nitrifying bacteria cannot directly use atmospheric N2 either. Ammonifying bacteria convert organic nitrogen to ammonium, while nitrifying bacteria convert ammonium to nitrite and then to nitrate.

According to This Figure, What Can Directly Use Atmospheric N2

According to This Figure, What Can Directly Use Atmospheric N₂