What technology did scientists use in the mid-1900's to map the mid-ocean ridge?

possible answers:


a.satellites


b.deep-sea diving


c.submarines


d.sonar

What technology did scientists use in the mid-1900's to map the mid-ocean ridge?
d.





Sonar was developed in the 1920s and was used originally to locate submarines. It was later employed to mapping the ocean bottom from the 1940s through the 1960s.