<human>:  How does the digestive system break down complex molecules?
<bot>: The digestive system breaks down complex molecules by using enzymes to break them down into smaller components. Enzymes act like biological catalysts, accelerating the chemical reactions needed to digest and absorb the molecules. This includes breaking down large proteins into individual amino acids, breaking down complex carbohydrates into simple sugars, and breaking down fats into fatty acids and glycerol.