Which of the following is true about passive sonar?

Passive sonar is a technology that primarily listens for sound waves in the environment rather than emitting its own signals. This characteristic allows it to detect sound waves produced by other sources, such as submarines, marine animals, or underwater geological activity. By analyzing these sounds, passive sonar systems can determine the location and movement of these sources without revealing their own presence.

In contrast, the other options refer to functionalities or characteristics that are not aligned with how passive sonar operates. For example, active sonar would be the system that emits sound waves to detect objects by measuring echoes, which is fundamentally different from the principle of passive sonar. This is why the correct identification of passive sonar’s role emphasizes its ability to detect external sounds rather than creating them or engaging actively.