The realm's prosperity and allegiance of all of its vassals. The relief shows people who came to pay tribute to the emperor. It exemplifies the emperor's enormous power over the whole dominion of the then huge Achaemenid empire, as well as respect and allegiance that everyone showed him. His almost divine authority is seen in the fact that he is the only one sitting.
Hi! The contralto is the lowest among the femal voice along with the most unique among females because it’s considered the main voice that males generally have. Thus making it uncommon/unique for females to have this voice. I hope this helped, Goodluck :)