| 1 | What is the danger level for humans and radioactivity? | |
| 2 | This radioactive form of nitrogen does not occur in nature. | |
| 3 | Then she found that pitchblende was more radioactive than uranium by itself. | |
| 4 | A green radioactive mineral that is a hydrous crystalline phosphate of uranium and copper. | |
| 5 | Without galactic assistance, I know of no other way to address the radioactive fallout problem. |