Radars can help meteorologists detect clouds and sailors detect submarines. Radars send out radio waves and record their echoes after the radio waves reflect off an object. Two radars send out radio waves with the same frequency. The first radar sends radio waves through the air. The second radar sends radio waves through the ocean. What is true about these radio waves? SC.7.P.10.3 A. They are visible. B. They are audible. C. They have different speeds D. They have the same wavelength