Question

1. choose the best answer.

in the 1920s, ______ equipment was invented to locate objects in the water.

telegraphy

radio

periscope

sonar

Explanation:

Telegraphy is for sending messages via electrical signals. Radio is for wireless communication. A periscope is for seeing over obstacles. Sonar uses sound waves to locate objects underwater. In the 1920s, sonar was invented for this purpose.

Answer:

sonar