MCQOPTIONS
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| 1. |
The ozone layer is at height of ________ kilometers from the surface of the Earth. |
| A. | 10 to 20 |
| B. | 20 to 30 |
| C. | 30 to 40 |
| D. | 40 to 50 |
| Answer» C. 30 to 40 | |