Final answer:
The Federal Trade Commission Act created an agency to investigate antitrust practices.
Step-by-step explanation:
The act that created an agency to investigate antitrust practices is the Federal Trade Commission Act. This act was passed by the United States Congress in 1914. The Federal Trade Commission (FTC) was established to promote fair competition and prevent unfair or deceptive business practices. The agency has the authority to investigate and take legal action against companies engaging in anticompetitive behavior.
Learn more about Federal Trade Commission Act