Final answer:
During the Gilded Age, when an industry was monopolized by one company or trust, workers often earned less because fewer businesses were competing for their services.
Step-by-step explanation:
When an industry was monopolized by one company or trust during the Gilded Age, workers often earned less because fewer businesses were competing for their services. Owners of monopolies had greater control over setting wages, and without competition, they had less incentive to pay workers higher wages. This exploitation of workers with lower wages and poor working conditions was a common characteristic of monopolies during the Gilded Age.