a combined transmitter and receiver called a transducer sends a sound pulse straight down into the water and the pulse moves through the water and bouces off the ocean bottom so that the transducer is able to pickup the reflected sound
That they are dry and not wet climates
<em>tæñgæ </em><em>ikaw </em><em>mama </em><em>mo </em><em>jahagdjshsajaj</em>