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.
Interference on AM and FM Radios. Toolbox. As the use of transmitters, receivers and communication devices increases, so do the disruptions in signal reception. As a rule, FM receivers are less affected by crackling noises than AM receivers. Conversely, AM radio is not as susceptible to the signal reflection phenomena.