erinaphillips4719 erinaphillips4719 01-02-2024 Biology contestada Respiration is defined asA. Taking in O₂ and expelling CO₂ by the heartB. Taking in CO₂ and expelling O₂ by the lungsC. Taking in CO₂ and expelling O₂ by the heartD. Taking in O₂ and expelling CO₂ by the lungs