What did ponyboy mean by saying "nothing gold can stay"

Which of these sentences is the correct one?

What do you call a person who is mean in school?

Match the definition to the word. 1. person or group opposing or hostile to another person or group propaganda 2. arranged in the order in which the events happened spatial 3. based upon reason; a rational approach to something logic 4. a method or system used to accomplish something adversary 5. having to do with space technique 6. coming one after another, in series, or in order chronological 7. the spreading of opinions or beliefs implied 8. suggested, indicated, or understood without express statement sequence