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

Fact 2: Carbon is in every organic compound.

Given the two facts above, answer the question "What increases the amount of carbon in soil?" with the following options: 
- oxygen
 - decomposition
 - nutrients
 - chlorofluorocarbons
 - rainfall
 - fossil fuels
 - wind
 - water


 

  decomposition       