Final answer:
Labor unions formed during industrialization in response to difficult working conditions, uniting workers to promote their rights and due to the ineffective individual protests against powerful factory owners.
Step-by-step explanation:
The formation of labor unions was a significant effect of industrialization in the late 1800s due to the poor working conditions and the workers' desire for change. The industrial revolution led to longer work hours in hazardous conditions, triggering the need for collective action. Early labor unions, such as the National Labor Union and the Knights of Labor, welcomed a diverse membership and sought to improve worker rights through owner engagement and political advocacy. However, they faced challenges due to the public's negative reactions to violent strikes. Over time, more formal structures such as the American Federation of Labor rose to prominence, helping to negotiate better work conditions. Despite setbacks, the labor movement saw significant growth and resulted in legal reforms favoring worker organization and collective bargaining.