Can I get help to solve these problems please?

4. Which of the following components of program state are shared across threads in a multithreaded process? (I point) (b) Stack (b) Heap c) Register values (d) Global variables 5. What is the essential cause in the difference in cost between a context switch for processes and kernel-level threads? (Assume the threads are part of the same process) (3 point) 6. In the discussion of User-Level-Thread(UTL)s versus Kermel-Levl Thread(KTL)s, t says that a disadvantage of UTLs is the when a a UTL exccutes a system call, not only is that thread blocked, but also all of the threads within the process are blocked. Why is that so? (3 points)