Nothing really. Someone else already wrote that Android is technically Linux. But you can also get “regular” Linux on mobile devices, it’s just a matter of using a distribution with mobile-friendly UI as well as getting driver support for the phone’s hardware. Ubuntu touch exists for example, but only works on a limited number of devices and even on supported devices it’s not really suitable for the average user yet.
Nothing really. Someone else already wrote that Android is technically Linux. But you can also get “regular” Linux on mobile devices, it’s just a matter of using a distribution with mobile-friendly UI as well as getting driver support for the phone’s hardware. Ubuntu touch exists for example, but only works on a limited number of devices and even on supported devices it’s not really suitable for the average user yet.