Which of the following is a characteristic feature of mechanical ignition systems?

A characteristic feature of mechanical ignition systems is the physical movement of components for timing. In these systems, the ignition timing is controlled by mechanical parts such as the distributor, points, and cam. The physical interaction between these components leads to the opening and closing of the ignition circuit, ensuring the timing of the spark that ignites the air-fuel mixture in the engine. This design relies on mechanical principles rather than electronic controls, marking a significant difference in how ignition is managed compared to more modern electronic ignition systems.

The reliance on electronic sensors is a hallmark of electronic ignition systems, which utilize sensors to determine the precise timing of the spark. Dependency on battery power can be found in both mechanical and electronic ignition systems, thus it does not specifically characterize mechanical systems. The use of specialized tuning software is typical for electronic systems where calibration and adjustments can be made via computer interfaces, not for mechanical ignition systems that function through physical adjustment and manual tuning.