Progressive upton sinclair is credited with

a writing a novel called the jungle that told about conditions in the meat-packing plants of chicago.

b singing various reform acts and speaking out against trusts.

c writing a series of articles about coal mining .

d creating blue laws.

c. have a great day ~ma.tiah

explanation:

the addition to geographic boundaries that might have  kept the people of the huang river civilization from traveling to far distance region is that they had learned about the other river valley civilizations but feared contact would bring invasion.

hope this .

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