Carbon dioxide concentrations in the air have increased over the last decade dramatically, and decades have 10 years. Given these facts, concentrations of what in the air have increased over the last 10 years dramatically among the following options:
- chlorofluorocarbons
 - fossil fuels
 - ozone
 - Greenhouse gases
 - Greenhouse gasses
 - oxygen
 - carbon dioxide
 - air molecules


 

       carbon dioxide  