| 25. | The normal threshold of hearing is around | |||||||
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| 26. | The refrigerant commonly used for domestic refrigerators is | |||||||
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| 27. | The normal term of office for which the President and Vice-President of the International Court of Justice are elected is | |||||||
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| 28. | The ozone layer is being destroyed by chlorofluorocarbons. In this regard which do you consider as the most harmful? | |||||||
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