The three boxes in this diagram represent the three major biosynthetic pathways in aerobic respiration. Arrows represent net reactants or products Arrows numbered 4,8 and 12 can all be

Step-by-step solution

Pathway A is glycolysis, pathway B is the krebs' cycle and pathway C is oxidative phosphorylation Arrow 1 - ADP or NAD ⁺ Arrow 2 - Pyrunate Arrow 3 - NADH Arrow 4 - ATP Arrow 5 - ADP, NAD ⁺ or FAD Arrow 6 and 7 - FADH ₂ and NADH (either one can be 6 or 7 ) Arrow 8 - ATP or CO ₂ Arrow 9 and 10- O ₂ and ADP (either one can be 9 or 10 ) Arrow 11 and 12- H ₂ O and ATP (either one can be 11 or 12)