Complex sentence: In the United States, health insurance marketplaces, also called health exchanges, are organizations in each state through which people can purchase health insurance that complies with the Patient Protection and Affordable Care Act (ACA, known colloquially as "Obamacare").
Split into simpler sentences: In the United States, health insurance marketplaces, also called health exchanges, are organizations in each state through which people can purchase health insurance. At ACA health exchanges people can purchase health insurance that complies with the Patient Protection and Affordable Care Act (ACA, known colloquially as "Obamacare").