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

Fact 2: Algae Algae Green algae are the simplest of green plants.

Given the two facts above, answer the question "What is formed when sediments push down on green plants?" with the following options: 
- water
 - moss
 - tar
 - dirt
 - Urea
 - coal
 - oil
 - grass


 

       oil  