| Answer | Crossword Clue |
|---|---|
| NITROGEN | Most of the atmosphere |
| ARGON | Most common inert gas in the atmosphere |
| ARGON | Third-most common gas in the atmosphere |
| ARGON | Most abundant noble gas in the atmosphere |
| ARGON | Third-most abundant gas in the atmosphere |
| ARGON | Third most common gas in Earth's atmosphere |
