Steppes: Steppes are usually characterized by a semi-arid or continental climate. Extremes can be recorded in the summer of up to 45 °C (113 °F) and in winter, -50 °C (-58°F). Besides this huge difference between summer and winter, the differences between day and night are also very great.

African Savannah & North American Prairie: These regions have more rainfall and varied landscapes compared to the Steppe. Nomadic herding existed, but wasn't the sole way of life.

Siberian Tundra: Colder, less rain, permafrost. Not ideal for grazing animals. Nomadic herding is less prevalent.

Therefore, the Central Asian Steppe, with its extreme climate, limited rainfall, and historical dependence on nomadic herding, best fits the description in the statement.