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

Fact 2: Plant respiration and decomposition of dead plant life consume dissolved oxygen in the water.

Given the two facts above, answer the question "What increases the amount of organic matter in soil?" with the following options: 
- chemical reaction
 - one celled organisms
 - aerobic capacity
 - nutrients
 - fossil fuels
 - Dissolved oxygen
 - chemical changes
 - swamp vegetation


 

      Dissolved oxygen   