6,7 answer both questions. Data structure c++

6) An application for a tree is a) caching Web pages in a browser so we can use the "back" button b) file directory structure c) Checking packets in the order in which they come in 7) If the time for a process is a constant and does not vary with the number of inputs this is )O(n2) b) O(n) c) 0(1)