Why Radio waves all travel at the speed of light, about 300,000,000 meters per second. Since speed equals frequency times wavelength, the product of the two is fixed, so raising one must lower the other. That is the inverse relationship captured by wavelength in meters = 300 divided by frequency in MHz: at 3.5 MHz the wave is about 80 meters long, while at 146 MHz it is only about 2 meters.
Watch out The choice saying wavelength grows with frequency has the relationship backwards, and path length has nothing to do with it, distance traveled does not change a wave's frequency or wavelength.
300 / MHz = meters. Higher frequency, shorter wave: 2 meters is way up at 146 MHz, 80 meters is down at 3.5 MHz.