3. What is virtual memory and how does it apply to demand paging? 34. What are the conceptual stages through which a process moves while being managed by the operating system? 35. Describe how a process might move through the various process states. Create specific reasons why this process moves from one state to another. 36. What is a process control block? 37. How is each conceptual stage represented in the OS? 38. What is a context switch?