Why did the tang dynasty create a bureaucracy?

How does the grapes of wrath identify the effects of americans' views on the dust bowl? the story is a depiction of oklahoma farmers and the difficulties they experienced migrating to california. the story accurately describes the impact the california vineyard industry had on migrant workers. the story covers the rise of corporate farming and the devaluation of the small family farms that dotted the great plains. the story is an allegory for the conflicts between american values and the rise of the communist party in the united states.

What were some of the most important native items adopted by europeans ? what impact did they have on european life ?

Which events are correlated but do not necessarily have a causal relationship?