Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation. In order from highest to lowest energy, the sections of the EM spectrum are named: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.
A barometer is a tool, not a variable. A barometer measures barometric or air pressure, which is a variable that meteorologists use to predict the weather.
Answer: A dune is a mound of sand formed by the wind, usually along the beach or in a desert. Dunes can also be formed by strong currents beneath the water.