Test understanding of physiological and molecular mechanisms by which regular aerobic exercise improves metabolic health and reduces insulin resistance in adults, including acute vs. chronic adaptations (skeletal muscle GLUT4 translocation and insulin signaling, AMPK activation, mitochondrial biogenesis and oxidative capacity, lipid oxidation, adipose tissue function and adipokines, hepatic glucose production, endothelial function, and systemic inflammation), the influence of training parameters (intensity, duration, frequency) on these pathways, and the ability to interpret evidence and biomarkers (e.g., euglycemic clamp, HOMA-IR, HbA1c) to explain causal links and exercise-prescription implications for adult populations.