Parts of a device that use radio waves. On the left is a box labeled A. On the right is a box labeled B. There is a vector pointing up from Box A and a vector pointing down to Box B. Arrows pointing left from Box A to Box B are labeled Radio waves travel through the air. Which part, A or B, captures, amplifies, and demodulates radio waves? Which part , A or B, modulates, amplifies, and sends out radio waves?