You are presented with the question "What increases the amount of carbon-containing compounds in the soil?" and the following answer choices: 
- nitrogen fixation
 - Greenhouse gasses
 - fossil fuels
 - chlorofluorocarbons
 - freezing
 - erosion
 - rainfall
 - decomposition

Now knowing that decomposition increases amount of organic matter in soil and organic Matter Organic matter is the varied array of carbon-containing compounds in the soil, choose the best answer.


 

        decomposition 