13. (4pts) Briefly describe what jacketing is. 14. (10pts) Explain why, when a ULT blocks for I/O, all ULTs are blocked. Give examples. 15. (10pts) If a process exits and there are still threads belonging to that process running, will they continue to run? Briefly explain why or why not? 16. (10pts) Consider an environment in which there is a one-to-one mapping between user-level threads and kernel-level threads that allows one or more threads within a process to issue blocking system calls while other threads continue to run. Explain why this model can make multithreaded programs run faster than their singlethreaded counterparts on a uniprocessor computer