Ii-Aerobic organisms zeentaka, izilwanyana ezanyisayo, kunye nezirhubuluzayo – zifuna i-oxygen ukuze zikwazi ukukhulula i-energy eyakuthi ihambe nge-cellular respiration, ngenkqubo ekuthiwa yi-metabolism ye-energy-rich molecules njenge-glucose. Ukuphefumla yenye yeendlela zokuzisa i-oxygen apho ifuneka khona emzimbeni kuze kususe ne- carbon dioxide.