Final answer:
The Affordable Care Act prohibits health insurance companies from denying coverage based on preexisting conditions.
Step-by-step explanation:
The Affordable Care Act (ACA), also known as Obamacare, prohibits health insurance companies from denying coverage to individuals with preexisting conditions. This means that a health insurance policy cannot be contested or rejected based on a preexisting medical condition. The ACA has significantly reduced the number of uninsured Americans and has made healthcare more accessible and affordable for many people.