Living things get rid of wasted by the process of

While the answer of this could be decomposition, the general breakdown of organic material into it's component parts, this could also be when during metabolic processes, an organism generates heat, which is radiated away and the energy of which is essentially "wasted", not serving any process.

Hope this helped :)

oxygen +1 most likely

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves