Answer:
I think the answer is C
Explanation:
No matter what African American soldiers did in the war they were not treated equally. Even after all the work they put in, they will still viewed the same. Nothing had changed.
The workers didn't learn how to completely manufacture a certain item. Instead, they learned a certain part of the process in manufacturing such item and they will repeat such process again and again, all day long. This is how the development of the industry impacted the way people lived and worked.
Andrew Johnson's behavior in office hurt the cause of the Reconstruction era, since he abandoned many of the more-liberal policies that he had trumpeted earlier, leading to a federal abandonment of the oversight process in the South.
hope this helps :)