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Human Biology: The 40-Square-Meter Studio Apartment

The human small intestine unfolds to cover a surface area of nearly 40 square meters, roughly the size of a studio apartment, to maximize nutrient absorption into the bloodstream. Maya and Daniel explain how the body categorizes food into fuel and building materials, focusing on the high energy density of fats versus the structural role of amino acids. Understanding the distinction between basal metabolic rate and active energy expenditure explains why the brain and liver consume seventy percent of daily calories even during rest. The chemical process illustrates how enzymes like salivary amylase transform tasteless starch into sweet maltose within seconds of chewing.