Good Riddles

Question: What has 4 fingers and a thumb, but is not living?

Question: A teacher decides to give a pop quiz one day but all of her students refuse to take the quiz thinking that the teacher will call off the quiz. She can give only one of these students a detention for skipping the quiz. All of the students know each other's names and if a student knows he/she is getting a detention they take the quiz.

How can she threaten her students with the single detention so they all take the quiz?

Question: I take what you receive and surrender it all by waving my flag.What am I?

Question: What demands an answer, but asks no question?

Question: I move slowly but I'm dead. I leave and then I'm back.I'm clear and then I'm red. I'm many neurotics' snack. What am I?