What method do logic functions use to express pre-determined operations?

The correct answer is based on the fact that logic functions rely heavily on electrical signals to represent and perform operations. In logic circuits, especially in digital electronics, electrical signals—typically represented as high (1) and low (0) voltages—are used to perform logical operations such as AND, OR, NOT, and others. These operations form the backbone of computing and digital processing, allowing for the manipulation of binary data.

Mechanical relays, while they can be used in older electronic systems, do not primarily express logic functions as they rely on physical movement and contacts rather than electronic signals. Direct transmittal involves the straightforward sending of information, which doesn’t encompass the nuanced operations of logic functions. Servomechanisms are used for control systems that require feedback for accuracy, but they do not represent logic operations as they operate based on mechanical components rather than logical expressions derived from electrical signals.

Thus, the use of electrical signals in logic functions is essential for enabling the computation and processing capabilities of digital systems.