Understanding the Material World is the “biological old regime” which was an overwhelmingly agricultural world where 80% of the population were peasant, who lived on the land and were told to produce food for themselves and the rest of the population. Climate change had an effect on the population since climate affect the number of people that agriculture could support. The agricultural revolution involved the domestication of animals. The Nomads the Eurasian steppe is a great grassland which stretches across the continent. Since it is not amenable to agriculture, people living there has to obtain a living by hunting and gathering and following herds. These people had a peaceful relationship with those in the cities. Due to the nomadic