The term ____ refers to the fact that the NAND gate can be easily changed into other logic functions such as INVERTER, AND, OR, and NOR gates.

The term "universal function" describes a logic gate that can be configured to perform any logical operation, which is precisely what the NAND gate does. Universality in this context means that with enough NAND gates, you can create any other gate or combination of gates, including INVERTER, AND, OR, and NOR functions. This versatility is what makes NAND gates particularly valuable in digital design, as they serve as a foundation for building more complex circuits.

In digital electronics, along with the NOR gate, the NAND gate is often singled out as a universal gate due to its capability to replicate all other basic logic gates. This means not only can a NAND gate be used to form these other gates, but it can also be used in configurations to build entire circuits covering a vast array of digital applications. The importance of this feature becomes clear when considering circuit minimization and design simplification, as the ability to use one type of gate to realize all necessary functions can lead to reduced costs and improved reliability in electronic designs.