question: What is common about the surviving mosaics from the 7th-9th centuries ?
answer: almost all represent Saint Demetrius
turker_answer: What is common among the surviving mosaics from the 7th-9th centuries , is that almost all represent Saint Demetrius .
rule-based: Common about the surviving mosaics from the 7th-9th centuries is almost all represent Saint Demetrius .