What role do transponders play in the IFF system?

Transponders are critical components of the Identification Friend or Foe (IFF) system. Their primary role is to respond to specific interrogations from radar systems by transmitting identification information. This response helps differentiate friendly aircraft from potentially hostile ones, thereby enhancing situational awareness in military and air traffic control scenarios. When an IFF-equipped transponder receives an interrogation signal, it sends back a coded reply that indicates the identity of the aircraft, assisting controllers and other aircraft in recognizing whether the plane is friend or foe.

The other options, while relevant in the broader context of aviation and technology, do not accurately describe the transponder's function within the IFF system. For instance, transmitting flight plans is a feature of different systems designed for air traffic management, and analyzing weather patterns or generating navigation data falls outside the primary responsibilities of transponders.