Respiration is the physical act of inspiration and exhalation of oxygen. Gas exchange is what happens in the lungs to use the oxygen that is brought in and expel the Carbon Dioxide brought back into the lungs from the cells. Respiration is the physical act of inspiration and exhalation of oxygen.
Definition of polyphony. : a style of musical composition employing two or more simultaneous but relatively independent melodic lines : counterpoint.
Homophony is when you have multiple parts moving together with the same rhythm to create harmony. Something like this. You can see here that the rhythm on every line is the same, though they do move in contrary motion, have different notes, etc. This creates harmony, and is what makes it homophonic. polyphony however, is when you have separate lines moving with rhythmic independence, like in a counterpoint work, or a fugue.