The amount of silk increased
B) They had a complex civilization that was destroyed by the Spanish conquerors.
By the time of the Spanish invasion, the Aztecs had devloped a strong civilizations, they had a system of trade & commerce and were quite wealthy. They also had a primitive form of "police" and a banking system.
They were used as slave labourers
Apparently, all of the names on the map are Irish, so the map suggests that Irish immigrants may take over the United States by the 1900s.
You may well be right about people's fears that immigrants, lots of them from Ireland, would overrun the country. Look up when the potato famine was, though. The map may be from the early 1900s, but, if so, not about the potato famine in Ireland.
