Fact 1: Gases released during the use of fossil fuels causes global warming.

Fact 2: Oil is a fossil fuel.

Given the two facts above, answer the question "gases released from the use of what causes global warming?" with the following options: 
- CO2
 - coal
 - CO 2
 - h2o
 - hydrogen
 - cooking
 - oil
 - CFCs


 

       oil  