Which is known as the most important software that runs on a computer?

The most important software that runs on a computer is the operating system. The operating system acts as an intermediary between the hardware of the computer and the application software, facilitating the execution of the latter. It manages system resources such as the CPU, memory, storage, and input/output devices, ensuring that various applications can run harmoniously without conflicts.

Without an operating system, a computer would not be able to function as it does; it would be incapable of executing programs or managing hardware components. It provides the necessary environment for application programs to operate and delivers essential services, such as file management, security, and user interface, making it a foundational layer of the computing experience.

Application software, utility software, and graphics software, while important, operate on top of the operating system. They cannot function independently without the operating system, emphasizing the latter's critical role in a computer's operation.