Russia joins the race to develop a coronavirus vaccine. Scientists there say they will have one ready for approval in august. Hello. Four tech giants and their executives have been under the spotlight in the United States, defending themselves against accusations they are too powerful and that their Business Practices are anti competitive. The congressional inquiry has been looking into the market dominance of facebook, amazon, google and apple. Mark zuckerberg, jeff bezos, tim cook and Sundar Pichai have all been questioned the culmination of a 13 month investigation by american lawmakers. Our tech correspondent James Clayton has been watching the hearing. These four titans of tech run the companies that are worth nearly £4 trillion. Today they were grilled over whether their companies are too big, and whether they stifle competition. The richest man in the world, jeff bezos, runs amazon, which accounts for around 40 of Online Retail in the states. Mark zuckerberg is the boss of face