The U.S. Justice Department and Google are concluding a landmark monopoly trial this week, with closing arguments set to begin on Thursday. The Justice Department has accused Google of illegally abusing its power as a monopoly in the search engine business, leading to reduced competition and lower-quality user experiences. Google argues its popularity is due to its superior search engine, not its business practices. The Justice Department's case against Google centered on the company's costly exclusive agreements with device makers and web browser companies.