and if we ever fail to do so, that s a mistake that we should correct. reporter: instagram embroiled in controversy since whistleblower frances haugens released internal documents about the harms of the social media platform on young people, particularly teenage girls. facebook s internal research is aware there are a variety of problems facing children on instagram that are they know severe harm is happening to children. reporter: mosseri today pushing back. i firmly believe that instagram and the internet more broadly can be a positive force in young people s lives. also sometimes young people can come to instagram dealing with difficult things in their lives. i believe that instagram can help in those critical moments. reporter: the instagram boss being asked about research this week that shows teens are easily able to find accounts advertising the sale of drugs like xanax and adderall. its algorithms even promoting these accounts to some users. accounts selling drugs