The primary functions of a mobile operating system include managing hardware resources, providing a user interface, and enabling application functionality. It acts as a bridge between the device hardware and applications, ensuring efficient resource allocation and communication. Essential features include task scheduling, memory management, and security protocols. The operating system also supports networking capabilities, application installation, and updates. Additionally, it offers a consistent experience across different device models, making it essential for performance and user satisfaction in mobile computing environments, whether Android, iOS, or others.