In hour one of Here & Now’s April 11, 2018 full broadcast, you’ve likely heard the saying: “The only way to stop a bad guy with a gun is a good guy with a gun.” But what is the true number of defensive gun uses? We speak with two researchers who have gone back and forth on that question. Also, the latest on Facebook CEO Mark Zuckerberg testifying before members of Congress for the second day Wednesday. And we talk with one man whose company aims to address both pollution and poverty by building facilities where plastic collectors can bring their wares and earn cash or credit in an online account.