No they are not.
You can't delete any of your questions or answers if you haven't registered. When my question has upvotes and unanswered for long time, it get deleted.
Valid unanswered questions will stay on the site forever, so they can be answered.Invalid questions, questions which break the rules or the law are deleted by Supervisors.
"Featured" questions are unanswered questions that Supervisors feel are interesting or important; it gives them more visibility, perhaps because they have remained unanswered for a long time.
That is one of the "hot" unanswered questions in theoretical physics.
Some post questions that are not important in their kind of what people are searching for. I suggest you send important questions(highly educated questions)so people could see it. If it doesn't work, ask your friends to answer your questions. I help people's unanswered questions because I don't want them to wait for a long time just for their question to be answered.
Not all - since there are new questions being added all the time. Additionally - some questions may stay unanswered for a long time - depending on the subject - and whether someone knowledgeable stumbles on it.
Some unanswered questions about the constellation Draco include the exact nature and origin of its shifting position in the sky over time, the possible presence of undiscovered celestial objects within its boundaries, and the significance of its mythological representation in various cultures. Further research and observation may help in unraveling these mysteries.
Archive Researchers tackle questions that have sat unanswered for long periods of time. Some of these are more difficult questions and require some research. They may recommend that the more interesting selections become Featured Questions.
The main reason why questions about pre-historic people remain unanswered is due to the lack of written records or documentation from that time period. Without written language or historical records, researchers must rely on archaeological evidence to piece together information about prehistoric cultures and societies, which can be limited or incomplete.
This is unanswerable because people add and answer questions all the time, so the number is always changing.
Using this is a waste of time, you ask question's and you expect answer's but all you get is some crappy unanswered/relevant questions similar to yours.
Of coarse that's why the bad people don't go to jail every time!