The mobile phones band in the UHF and SHF are totally silent because nature doesn't produce RF in that part of the spectrum. We are accustomized to the regular RF background but not to frequencies that were never present. Plus there is experimental evidence of resonance of subcellular structures at many frequencies. As the water molecule resonate at the same exact wavelength of your microwave oven so other molecules resonate at different frequencies making some chemical reaction faster,.some slower, some impossible.