None, plastic is poison. There was a scientific study that shows that people whom drink from plastic bottles/cups are more depressed throughout their lives than those who drink from glass. Plastic also lingers, and helps the pollution we already deal with- that will kill us eventually. It does not waste away like paper; though we can recycle it, people often just trash their bottles carelessly, without thinking of their environment. <span />
Amplitude determines the loudness of sound. Loudness is proportional to the square of the amplitude of the vibrating body which produces sound. ... Less the frequency, deep is the sound.
