Final answer:
Medicare is the federal health insurance program exclusively for individuals 65 or older, established to help seniors with medical costs not covered by standard insurance.
Step-by-step explanation:
Individuals age 65 or older are exclusively eligible for Medicare, which is a federal health insurance program. Medicare was established as part of the Social Security Act of 1965 to address the fact that less than half of Americans above the age of sixty-five had any medical insurance. This program helps seniors with medical costs, though it does not cover all expenses such as dental care, eyeglasses, and certain prescriptions. Elderly individuals can choose from different Medicare plans, such as Plan A for hospital coverage and Plan B for medical insurance similar to private employer plans.