9. What is SONAR? A system for the detection of e objects underwater by using GPS A system for the detection of objects underwater by using E e lasers A system for the detection of e objects underwater by using E sound waves A system for the detection of e objects underwater by using light E waves

The correct answer is: A system for the detection of objects underwater by using sound waves.<br /><br />Explanation: SONAR, which stands for Sound Navigation and Ranging, is a technique that uses sound propagation to navigate, communicate with, or detect objects on or under the surface of the water, such as other vessels or underwater terrains. It works by emitting sound waves that travel through the water and bounce back when they hit an object. By measuring the time it takes for the sound waves to return, the distance to the object can be calculated. This technology is commonly used in submarines, ships, and by marine biologists to study underwater environments.