Answer:
How societies are similar and different.
Step-by-step explanation:
The historian is analyzing sculptures from two different regions (Greece and Rome) that were very similar in some fields, going so far as to be impossible to distinguish one from the other, but totally different from each other, presenting totally different aspects. If the historian is making a comparison of sculptures based on the region, society and culture in which they are inserted, this historian is analyzing how these societies were similar and different at the same time.