What are the most abundant greenhouse gases in Earth's atmosphere
The most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order:

Water vapor
Carbon dioxide
Methane
Nitrous oxide
Ozone
Chlorofluorocarbons
Hydrofluorocarbons
Perfluorocarbons
Instruction: What are the most abundant greenhouse gases in Earth's atmosphere
Context: 
Response: The most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order:

Water vapor
Carbon dioxide
Methane
Nitrous oxide
Ozone
Chlorofluorocarbons
Hydrofluorocarbons
Perfluorocarbons