Fact 1: Decomposition increases amount of organic matter in soil.

Fact 2: Organic Matter Organic matter is the varied array of carbon-containing compounds in the soil.

Given the two facts above, answer the question "What increases the amount of carbon-containing compounds in the soil?" with the following options: 
- nitrogen fixation
 - Greenhouse gasses
 - fossil fuels
 - chlorofluorocarbons
 - freezing
 - erosion
 - rainfall
 - decomposition


 

        decomposition 