The responsibilities held by the federal government among the options you provided are:
- **Protecting national parks**: This is a federal responsibility, as national parks are managed by the National Park Service, which is part of the U.S. Department of the Interior.
- **Administering healthcare**: The federal government plays a role in administering healthcare through programs like Medicare and Medicaid.
- **Providing social security**: Social Security is a federal program that provides financial assistance to retirees, disabled individuals, and survivors.
The other options listed—managing intercity traffic, creating garbage collection services, and chartering city governments—are generally responsibilities held by state and local governments rather than the federal government.