The ability of a system to do more than one task at a time is accomplished by several means is

Multitasking

Explanation:

The ability of a system to do more than one task at a time is accomplished by several means is called multitasking.

When referring to computers and OS, the term “multitasking” means that the system is capable of performing and executing more than one operation at a time. It is important to take into account that no matter whether the user runs a program or accesses to Internet, every new task will consume system´s RAM and/or storage resources eventually producing a slow-down effect among other situations.