| Answer | Crossword Clue |
|---|---|
| AEONS | How long it takes mountains to form |
| EONS | How long it takes mountains to form |
| EONS | How long it takes canyons to form |
| MSEC | How long it takes light to travel 186 mi. |
| NSEC | About how long it takes light to travel a ft. |
| EON | How long it might take for a mountain to form |
