Fact 1: Oil is formed by layers of sediment pushing down on decomposing algae.

Fact 2: Fossil fuels like coal and oil are ancient biomass fuel.

Given the two facts above, answer the question "What is a product of layers of sediment pushing down on decomposing algae over time?" with the following options: 
- Fungus
 - Greenhouse gases
 - Fossil fuels
 - Calcium carbonate
 - salinity
 - Sand
 - contamination
 - Water


 

   Fossil fuels      