Kernel, System services and Application services constitute the operating system. The user or task sits at the lowest privilege level and can not access the resource available at higher privilege levels directly. Similarly, Task-1, Task-2 and Task-3 occupy different memory blocks and they are protected from each other.
A microprocessor such as 8086 does not provide this kind of protection. The Memory Management Unit (MMU) of advanced microprocessors such as 80286 incorporates this kind of protection for a multi-user operating system.