Final answer:
The Sherman Antitrust Act prevents monopolies and conspiracies from fixing prices, fixing bids, or dividing a market between competitors.
Step-by-step explanation:
The act that prevents monopolies and conspiracies from fixing prices, fixing bids, or dividing a market between competitors is the Sherman Antitrust Act. Passed in 1890, it gave the government the power to break up corporations that were acting in restraint of free trade by forming monopolies or engaging in other practices that artificially raise prices.