Final answer:
The landmark legislation passed during Benjamin Harrison's presidency was the Sherman Antitrust Act of 1890, which aimed to prevent businesses from monopolizing markets and engaging in unfair practices.
Step-by-step explanation:
The landmark legislation passed during Benjamin Harrison's presidency was the Sherman Antitrust Act of 1890.
The Sherman Antitrust Act was designed to prevent businesses from monopolizing markets and engaging in unfair business practices. It aimed to promote competition and protect consumers. The act gave the federal government the power to investigate and prosecute companies that were found to be engaged in anti-competitive behavior.
For example, the act was used to break up Standard Oil, a powerful monopoly in the oil industry, into smaller companies. It also paved the way for future antitrust legislation and the regulation of business practices in the United States.