Diabetes disrupts the body's ability to properly utilize glucose, leading to insufficient energy production, which manifests as muscle weakness and fatigue. The primary process for generating energy (ATP) from glucose is cellular respiration. Model (1) accurately depicts this process, showing glucose ($\text{C}_6\text{H}_{12}\text{O}_6$) and oxygen ($\text{O}_2$) as reactants, yielding carbon dioxide ($\text{CO}_2$), water ($\text{H}_2\text{O}$), and ATP (energy) as products. This model correctly summarizes the biochemical pathway that is impaired in diabetic individuals, explaining their symptoms.