Define the following terms:
$(a)$ Ground waves
$(b)$ Trade winds

(N/A) Ground waves: These are radio waves that travel along the surface of the Earth. They are typically used for low-frequency and medium-frequency communication. Because they follow the curvature of the Earth,they can travel beyond the horizon,but they are heavily attenuated by the Earth's surface.
$(b)$ Trade winds: These are prevailing patterns of easterly surface winds found in the tropics,within the lower portion of the Earth's atmosphere,in the lower section of the troposphere near the Earth's equator. They blow from the subtropical high-pressure belts towards the equatorial low-pressure belt.