Answer:
A monopoly is a company or business that dominates a particular market to such an extent that there is no viable competition to that company; Antitrust laws prevent monopolies by breaking up or limiting monopolies' size, allowing other companies to enter a market.
Antitrust laws are needed because if a monopoly does not have any other serious competition in a market, they have greater liberty when it comes to prices and quality.
Step-by-step explanation:
Reworded the other person's work as to better explain it.