Which operating system is designed for Apple's smartphones and tablets?

The operating system designed specifically for Apple's smartphones and tablets is iOS. This platform optimizes the user experience on mobile devices by focusing on touch-based interaction, app functionality, and seamless integration with other Apple services. iOS is known for its user-friendly interface, robust security features, and a vast ecosystem of applications available through the App Store.

Apple Mac OS, while also developed by Apple, is tailored for desktop and laptop computers rather than mobile devices. Microsoft Windows is a distinct operating system primarily used on PCs and certain tablet devices, but it does not power Apple's smartphones or tablets. Linux serves as an open-source operating system used in various applications, but it is not specific to Apple's mobile technology. Therefore, iOS is the clear choice when referring to the operating system for Apple's mobile products.