3 stages of cellular respiration:
0. Glycolysis, = It happens in the cytoplasm. It breaks down glucose to pyruvic acid. It does not use oxygen.
,1. Krebs Cycle, = It happens inside the mitochondria (matrix). It uses pyruvate to produce ATP. Its other names are Tricarboxylic acid and Citric acid cycle. It does not use oxygen but produces carbon dioxide.
,2. Electron Transport Chain, = It also happens inside the mitochondria (intermembrane space). It uses the NADH and FADH produced from the Krebs Cycle. It also uses oxygen to produce water.
ANSWER: C. Electron Transport Chain only