For each of the following situations, draw an ER diagram that describes it. Consider each situation independently. (Multiple situations means multiple, separate ER diagrams in a correct homework solution.)

1. Park rangers have identifying ranger numbers, first and last names, and phone numbers. Rangers work at state parks. A ranger might not be working at any state park, might work at one state park, or might work at multiple state parks. Some state parks might not have any ranger working at them; some state parks have many rangers.
2. Some state parks have museums in them. Park museums have museum identifiers (numbers), names, hours of operation (stored as a simple string) and addresses. Each state park museum must be in exactly one state park. But state parks may or may not have museums, and might have multiple museums.
3. Some state parks are state historic parts. For state historic parks, the database stores the name of a historic building, the year the historic building was built, and a photograph of the historic building. Some state parks are parks with camping sites. For parks with camping sites, the database stores the number of camp sites, the number of cabins, and the number of indoor bathrooms. Some state parks are both historic and have camp sites; some are simply one or the other; some state parks are neither historic nor have camp sites..
4. Rangers can supervise parks. A ranger may not supervise any parks, or one, or several. For each park that a ranger supervises, the database will store the date the ranger became a supervisor at that park. A park must have at least one supervisor, and might have many supervisors. (For example, a small park might have one supervisor, a supervisor who also supervises other, nearby parks. But a big state park might have multiple supervisors, so that there can be one on duty 24 hours a day.)
5. Park rangers have identifying ranger numbers, first and last names, and phone numbers. Some park rangers have one or more special skills, like "speaks Spanish" or "can identify animal tracks". For each special skill a ranger has, the database stores a short description, plus the number of years the ranger has had the skill. Descriptions cannot identify a skill uniquely across the whole database, but can identify a skill for a particular ranger.