The CEOs of Apple, Google, Facebook, and Amazon testified before congress this week as part of an ongoing investigation into these companies. Some US lawmakers, along with legislators in Europe, are becoming increasingly concerned these companies have violated antitrust laws and are exercising monopoly power to crush smaller competitors. The hearing was 5 hours long, and see-sawed back and forth between questions about supposed anti-conservative bias in social media, and questions that actually had to do with the market power of these companies, along with one representative asking Sundar Pichai for technical support with his email. With all that, here are a few of the questions that we thought were the most important to the issues at hand. Get More Engadget: • Like us on Facebook: http://www.facebook.com/engadget • Follow us on Twitter: http://www.twitter.com/engadget • Follow us on Instagram: http://www.instagram.com/engadget • Read more: http://www.engadget.com/