This week, Amazon, Berkshire Hathaway, and JP Morgan decided they want to get into the health care business, forming a nonprofit that could provide insurance for their employees. This made us wonder: why does Amazon, which began as a retailer, think it can solve the problems of health care? And what is not in the scope of its ambition?  In our regular segment, Quality Assurance, where we take a second look at a news story of the week, Marketplace Tech host Molly Wood talks about it with Alexander Nazaryan, Senior Writer for Newsweek.