Glaciers advanced from Canada and retreated four or more times. Over a few million years, Puget Sound was carved and scoured by glaciers. Heavy Pressure. Glaciers containing up to 2,383 cubic miles of ice pushed over the Puget lowland.
AM stands for amplitude modulation, while FM stands for frequency modulation. In AM, the amplitude (the height or depth of the crests or troughs) changes, while in FM, the fre â¦ quency changes. Answered.
This is often what the term means, but as FM is a way to put information on a carrier, that type of modulation could be used on just about any signal you'd care to apply it to. Certainly communications and amateur radio use it frequently on frequencies outside the so-called FM broadcast band.