Final answer:
The request and release of resources are accomplished through system calls, which allow programs to interact with the operating system for resources such as memory or file handles.
Step-by-step explanation:
The request and release of resources are system calls. A system call is a way for programs to interact with the operating system. When a program needs to request or release resources, such as memory, file handles, or communication ports, it makes a system call. The operating system then handles the request, granting or releasing the resources as needed. System calls provide a controlled means for programs to request lower-level services provided by the operating system kernel.