Fact 1: Bacteria in soil convert atmospheric nitrogen into a form usable by plants.

Fact 2: Plants are the primary producers on earth.

Given the two facts above, answer the question "Bacteria in the soil convert what type of gas into a form that is used by producers?" with the following options: 
- energy
 - burning
 - food
 - Energy.
 - nitrogen
 - nutrients
 - Cooking
 - a solute


 

     nitrogen    