 |
| |||
| total amount of ozone; total ozone; total ozone amount; total amount | |||
| ozone total: 16 phrases in 4 subjects |
| Environment | 7 |
| Life sciences | 7 |
| Natural sciences | 1 |
| United Nations | 1 |
|
| |||
| total amount of ozone; total ozone; total ozone amount; total amount | |||
| ozone total: 16 phrases in 4 subjects |
| Environment | 7 |
| Life sciences | 7 |
| Natural sciences | 1 |
| United Nations | 1 |