What were the three social classes in Sumerian cities and how did they different?

Which of the following is an example of the pull factor known as economic migration? a. better educational opportunities pulling people towards a new country b. mexican laborers entering the us to work in agricultural jobs c. joining family members that are already in a new country d. crop failures driving people away from their country i am unsure on this question, i was thinking b? but i could be wrong.

Was the amassing of men, equipment, and supplies for the 1944 invasion of europe. operation varsity operation nordwind operation dragoon operation overload operation torch

Tension between the british. and boers was caused primarily by what things?