The Federal Trade Commission and 46 states sued Facebook Inc. on Wednesday, accusing the social-media behemoth of acquiring and freezing out small startups to crush competition.The FTC”s sweeping antitrust case plans to force Facebook to unwind its acquisitions of Whatsapp and Instagram, two of its landmark deals. The states filed a separate and identical lawsuit, stating that a lack of competition has harmed consumers, including by weakening privacy protections.The lawsuits arrive weeks after the Justice Department brought the case alleging Google was illegally managing a monopoly in its search business. Collectively, the cases reflect US worries over the power of dominant online platforms.