| Answer | Crossword Clue |
|---|---|
| BASAL | Pertaining to the lowest possible level |
| undreamed | Not thought to be possible (used to express pleasant surprise at the amount, extent, or level of something) |
| ecosphere | the part of the atmosphere in which it is possible to breathe normally without aid: the portion of the troposphere from sea level to an altitude of about 13,000 ft. (4000 m) |
| nadiral | pertaining to nadir (the lowest point of the heavens) |
| eustatic | pertaining to eustasy (a worldwide change in the sea level, also EUSTACY) |
| eustatically | EUSTATIC, pertaining to eustasy (a worldwide change in the sea level, also EUSTACY) |
| subsonic | noting or pertaining to a speed less than that of sound in air at the same height above sea level |
