We know this by dating the structures, evidence of life there long before anywhere else and by the Bible. You can also look into other sources of history too. There is a ton of info on Egypt provided by scrolls a old writing on stone tablets.
They became more interested in art
The Manchuria most parts of China provides us, being one of the most Chinese regions where heavy industries are concentrated due to the presence of the largest reserves of coal, as the steel industry is concentrated too in Manchuria
Camp fire they could use that for a lot in cold places
