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

Fact 2: Many orchids are rewarding indoor plants.

Given the two facts above, answer the question "bacteria in soil converts atmospheric nitrogen into a form usable by what?" with the following options: 
- bacteria
 - humans
 - density
 - Conifers
 - Roundworms
 - gravity
 - h2o
 - orchids


 

        orchids 