Final answer:
The role of labor unions changed as the economy changed due to factors such as the shift from manufacturing to service industries, globalization, increased competition, and workplace protection laws.
Step-by-step explanation:
The role of labor unions changed as the economy changed due to several factors. One major factor was the shift from manufacturing to service industries, which resulted in a decline in union membership as unions were historically stronger in manufacturing.
Additionally, globalization and increased competition from foreign producers also weakened the influence of labor unions. Another reason for the decline in union membership was the presence of workplace protection laws, which reduced the desire for unions as workers had legal protections in place.