Final answer:
Secondary radar technology was initially created during World War II to identify friendly aircraft using transponders, which marked a significant advancement in military operations and air traffic control.
Step-by-step explanation:
Secondary radar technology, also known as Secondary Surveillance Radar (SSR), was originally developed during World War II. Its primary purpose was to identify friendly aircraft known as Identification Friend or Foe (IFF). Unlike primary radar which simply detects objects by bouncing radio waves off them, secondary radar requires a transponder in the target aircraft to receive and respond to signals. This technology greatly improved air traffic control capabilities by allowing for the identification of individual aircraft on a radar display as well as obtaining additional information, such as altitude and identification code. Its invention was a significant advancement in both military operations and later in civil aviation.