Mark Zuckerberg, the CEO of Meta, will testify during a landmark social media trial in Los Angeles. The plaintiff, a now 20-year-old woman, is seeking to hold social media companies responsible for harms to children who use their platforms. Meta and YouTube are the two remaining defendants in the case, which TikTok and Snap settled. Zuckerberg’s testimony comes a week after the testimony of Adam Mosseri, the head of Meta’s Instagram. Zuckerberg is expected to face questions about Instagram's algorithm, the infinite nature of its platforms' feeds and other features the plaintiffs argue are designed to get users hooked.