Bacteria in soil convert atmospheric nitrogen into a form usable by plants, and bacteria are single-celled organisms. Given these facts, what in soil converts atmospheric nitrogen into a form usable by plants among the following options:
- compound of hydrogen oxygen
 - carbohydrates
 - single-celled organisms
 - excretory structures
 - peachleaf willow
 - members of their own species
 - It helps them survive
 - deoxyribonucleic acid


 

   single-celled organisms      