Final answer:
The main program in an operating system is called the Kernel, and it is responsible for managing the system's resources and providing essential services to other programs.
Step-by-step explanation:
The main program in an operating system is called the Kernel. The Kernel is the core of the operating system and is responsible for managing the system's resources, such as memory, processes, and input/output devices. It provides the essential services that allow other programs to run and interact with the hardware.
For example, when you open a web browser, it is the Kernel that handles the communication between the browser and the network card, allowing you to access web pages.
Other components, such as the File Manager and Directory, are important parts of an operating system, but the Kernel is the fundamental program that controls and coordinates all the other programs and processes.