Complex sentence: They assert that Egypt, almost alone, offers optimal climatic conditions favoring preservation of ancient manuscripts while, in the other hand, the papyri used in the east (Asia Minor and Greece) would not have survived due to the unfavourable climatic conditions.
Split into simpler sentences: They assert that Egypt, almost alone, offers optimal climatic conditions favoring preservation of ancient manuscripts. Thus, the papyri used in the east (Asia Minor and Greece) would not have survived due to the unfavorable climatic conditions.