Answer :
Workers in nineteenth century mines and mills faced difficult working conditions due to (A) dangerous machines, (B) low pay, and (C) poor air quality. However, "8 hour days" were never a problem and would have been a luxury as many workers had to work much longer days.
The correct answer is D) eight-hour days.
The element that was not a problem faced by workers in 19th-century mills or mines was eight-hour days.
The workers in the mills and the mines in the 19th century were forced to work during long periods of time in non-safety conditions. This increased the risk of accidents. The workers faced considerable problems such as low pay, poor air quality, and dangerous machines. Those problems were reasons why the considered to form the initial and incipient idea of labor unions.
