What type of information does secondary radar display?

Secondary radar primarily relies on aircraft that are equipped with transponders, which are devices that transmit specific data back to the radar system in response to interrogations. When an aircraft’s transponder receives a signal from the radar, it sends back information such as the aircraft's identification, altitude, speed, and sometimes additional data like squawk codes. This is crucial for air traffic control, as it enhances the accuracy and reliability of tracking aircraft compared to primary radar, which can only detect the presence of an object without providing detailed information.

In the context of the other options, the choice related to all flying objects would include both those with and without transponders, which secondary radar does not cover comprehensively. The option regarding weather conditions refers to meteorological data gathered through different systems, often involving dedicated weather radar rather than secondary radar. Lastly, data about ground operations would pertain to activities on the runway or taxiways, typically monitored through ground control systems that are separate from the function of secondary radar. Thus, the use of secondary radar is specifically linked to data provided by transponders on aircraft, making that the correct response.