Mark Zuckerberg testified that it's "very difficult" to enforce Instagram's age limits as he sought to defend the platform during a landmark trial over social media addiction. The chief executive officer of Meta Platforms was sharply questioned on the witness stand Wednesday about the company's efforts to attract and engage teenage users, and whether it adequately policed accounts belonging to children under 13, despite rules barring them from using the app. Zuckerberg said Meta has introduced some "proactive tools" to try to identify and remove accounts used by children under 13, but called it a "challenging" problem. Bloomberg News Senior Technology Reporter Kurt Wagner joins Bloomberg Businessweek Daily to discuss. He speaks with Carol Massar and Tim Stenovec.