Final answer:
The Centers for Medicare and Medicaid Services is the largest payer of health care services in the U.S., administering both Medicare, for those over 65 or with disabilities, and Medicaid for low-income individuals and families.
Step-by-step explanation:
The government agency that is the single largest payer of health care services in the United States is the Centers for Medicare and Medicaid Services (CMS). CMS administers the Medicare program, which provides health insurance primarily to people over sixty-five years old, as well as some younger individuals with disabilities. Medicare is a single-payer system, supported by taxes, and it pays for a substantial portion of the health care for the elderly in the U.S. In contrast, Medicaid, which is also overseen by CMS, offers assistance to individuals and families with low incomes and resources. Both Medicare and Medicaid are crucial elements of the U.S. healthcare system, and together they cover a vast range of Americans, making CMS the largest payer of health care services in the country.