- United States | 210, 210, 6
- Country in North America | 0, 210, 9
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- Americas | 0, 1k, 21
- Continent | 0, 3k, 59
- Earth | 0, 3k, 65
- Solar system | 0, 3k, 66
- Orion Arm | 0, 3k, 67
- Milky way | 15, 3k, 68
- Local group | 0, 3k, 69
- Virgo Supercluster | 0, 3k, 70
- Astronomy | 0, 3k, 77
- Natural science | 0, 37k, 827
- Science | 0, 41k, 938
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- Heavy water | 55, 55, 2