Which feature helps to determine a system's functionality?

The feature that helps to determine a system's functionality is performance characteristics. These characteristics define how well a system operates in terms of its efficiency, effectiveness, reliability, and various other metrics. Performance characteristics provide a measurable and actionable understanding of what a system can do, enabling stakeholders to assess whether the system meets the intended requirements and operational objectives. This understanding is critical in systems engineering, as it guides design decisions and informs users about the capabilities of the system.

In contrast, affordances refer to the properties of a system that suggest how it can be used, which may not directly relate to defining the system's functionality. Decision gates are checkpoints in a project that help determine whether to continue or revise a course of action based on performance or results, but they do not inherently define functionality. Feedback loops indicate how outputs of a system can influence its own inputs, which is crucial for ongoing adjustments and improvements but does not directly define what the system can do initially. Therefore, performance characteristics stand out as the primary feature for assessing system functionality.