The correct option is : "It helped them find enemy ships and planes."
The Radar is a system that uses electromagnetic waves to measure distances, altitudes, directions and speeds of static or mobile objects such as aircraft, ships, motorized vehicles, meteorological formations and the terrain itself. The current radar model was created in 1935 and developed mainly in England during the Second World War by the physicist Robert Watson-Watt. It was a remarkable tactical advantage for the Royal Air Force in the Battle of Britain, when it was still called RDF (Radio Direction Finding).
"declare and conduct war" was really the only real power granted to Congress under the Articles of Confederation which is why the Constitution was introduced please rate and thanks me