a source of something produces that something & cellular respiration is a source of energy for cell activities -> cellular extract gills matter for room activites cellular respiration produces energy for cell activites  cellular respiration produces energy for cell activites & cellular actions is when fight neutron matter from poison to wreck matter -> cellular repiration produces energy by extracting energy from food cellular repiration produces energy by extracting energy from food  cellular repiration flowers matter by extracting matter from poison & all cells perform cellular respiration -> all cells produce energy by extracting energy from food