Meta CEO Mark Zuckerberg is defending his company against clai that his platforms have harmed children. He took the stand yesterday in a landmark social media case. Zuckerberg faced hours of tough questioning, denying that Instagram was intentionally designed to be addictive.The case is seen as a bellwether that could have major implications for the social media industry. Let's bring in MSNOW reporter Jillian Frankel. Jillian, take us through what MARK ZUCKERBERG HAD TO SAY ON THE STAND.ANNA, THIS IS THE FI ...