Which of the following services is specifically excluded from Medicare coverage?

The correct answer is that cosmetic procedures are specifically excluded from Medicare coverage. Medicare generally does not cover procedures that are concerned solely with improving appearance rather than treating a medical condition. These cosmetic procedures are classified as elective and not deemed medically necessary, thus they do not fall under the benefits provided by Medicare.

In contrast, emergency medical services, preventive screenings, and hospital stays are essential components of Medicare coverage. Emergency medical services are crucial for addressing urgent health needs, preventive screenings help in early detection and prevention of diseases, and hospital stays are necessary for inpatient care. Each of these services plays a significant role in maintaining health and treating medical issues, which is why they are covered under the Medicare program.