Mosseri, who leads Instagram, is among the first major tech executives to testify in a growing wave of cases accusing platforms of harming young users. The current case targets Meta, Instagram’s parent company,

A typical teen’s day includes up to nine hours of texting, gaming, watching videos, and posting on multiple social networks — even while doing homework. It’s enough to make you wonder: Is my kid addicted to technology? Look around, and it’s easy to ...