| Answer | Crossword Clue |
|---|---|
| POS | Like natural numbers: Abbr. |
| POS | Like all natural numbers: Abbr. |
| ORD | Like some numbers: Abbr. |
| INTEGERS | Natural numbers. |
| ALEPH | ...-null (the number of natural numbers) |
| SYN | Not natural: Abbr. |
| ASTR | Natural science: Abbr. |
| OSU | Wolverines' natural enemy?: Abbr. |
| NOS | Some are natural: Abbr. |
| BTU | Abbr. on some natural gas bills |
| ECOL | Study of the natural world (abbr.) |
