You are presented with the question "What contributes to global warming?" and the following answer choices: 
- using wind farms
 - recycling
 - burning coal
 - Greenhouse gases
 - operating an automobile
 - chlorofluorocarbons
 - Greenhouse gasses
 - nuclear energy

Now knowing that operating an automobile usually requires fossil fuels and global warming is caused largely by fossil fuel use, choose the best answer.


 

     operating an automobile    