What role does a transponder play in aviation?

A transponder plays a crucial role in enhancing radar visibility, which is critical for maintaining safe airspace and facilitating air traffic control operations. When an aircraft's transponder is activated, it responds to interrogations from ground-based radar systems by sending back a coded signal that identifies the aircraft. This process allows air traffic controllers to distinguish between different aircraft on their radar displays and provides vital information such as altitude and flight identification. Enhanced radar visibility helps prevent collisions, contributing to overall air safety.

The other options do not accurately reflect the primary function of a transponder. While navigation can be aided by systems that incorporate transponder data, the transponder itself does not improve navigation capability. It also does not directly track weather changes, nor does it monitor fuel consumption. Thus, the correct answer emphasizes the critical safety feature that a transponder provides in enhancing an aircraft's visibility to air traffic control.