U.S. senators question Amazon on concerns it tracks employees, limits unionization

Four Democratic U.S. senators on Thursday sent a letter to Amazon.com Inc'sChief Executive Jeff Bezos, demanding answers over the company's alleged moves to track and monitor employees and limit unionization efforts.Democratic senators Brian Schatz, Elizabeth Warren, Bernie Sanders and Kirsten Gillibrand asked the company for details on the steps it takes to discourage workers from organizing, how it tracks workers who participate in strikes and the law firms Amazon contracts with for union avoi