Human: I need to learn more about the US healthcare system. Where should I start? Assistant: 
The best place to start is by researching the Affordable Care Act (ACA). This law, passed in 2010, has had a major impact on the US healthcare system and how it operates. It has helped millions of people gain access to health insurance, as well as improved coverage for those who already had insurance. You can find out more information about the ACA here: https://www.healthcare.gov/what-is-aca/.