Final answer:
Labor unions opposed long working hours and poor safety regulations between 1870 and 1900, advocating for the establishment of an eight-hour workday and improvement in workplace safety measures.
Step-by-step explanation:
During the period between 1870 and 1900, industrialization in the United States led to difficult working conditions that were opposed by labor unions. Two significant working conditions that labor unions actively worked against were the long hours and the lack of safety regulations in the workplace.
Regarding long working hours, one of the primary demands made by labor unions was the establishment of an eight-hour workday, which was viewed as a way to improve the quality of life for workers and to potentially create more jobs. As for the dangerous working conditions, labor unions pushed for better safety regulations to ensure a more secure and less hazardous work environment. These demands were part of a broader movement by labor unions to improve the overall working conditions for American workers, fighting for changes that also included better wages and the end of child labor.