I've had to do this so I know that:
--2500 BC--
Back in 2500 BC people spent there time in the Indus River Valley by farming (which the women did), hunting down for food (which the men did) while sometimes teaching their sons to do so as well, and getting water from the to rivers of Mesopotamia. (The Tigris river and the Euphrates river).
--Today--
But nowadays people still live there (I think) and do the same but of course don't hunt for food because there are supermarkets and they get water there as well but many people may still get water from the river.
I hope this helped! If it did, ask me more questions and I will be sure to answer them! :)
Your: is A the northern workers had a better work ethic
The situation prevailing in a market in which buyers and sellers are so numerous and well informed that all elements of monopoly are absent and the market price of a commodity is beyond the control of individual buyers and sellers.