| Answer | Crossword Clue |
|---|---|
| GASSES | Hydrogen and methane |
| GASSES | Hydrogen and methane (Var.) |
| GASES | Krypton and methane |
| GREENHOUSEGASES | Methane and ozone |
| GASES | Methane and butane |
| GASES | Butane and methane |
| GREENHOUSEGASES | Carbon dioxide and methane |
| ALKID | Combination of methane and metal: Chem. |
| GREENHOUSEGASES | CO2 and methane, to a ecoscientist |
