Which law did congress pass in 1890 to prohibit monopolies and trusts?

The Sherman Antitrust Act of 1890 was passed to ban monopolistic business practices. In a monopoly, there is no competition and the monopoly can wipe out small businesses (ie. If Verizon were allowed to buy up all cell phone companies, everyone would buy through Verizon, and a small startup cell phone company would never have a chance to survive). The Sherman Antitrust Act was also the first law passed to prohibit trusts.

ANSWER: Sherman Antitrust Act

Hope this helps! :)