Which compound made of carbon, hydrogen, and oxygen is a major source of energy for the human body?

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Carbohydrates are the body's most readily available source of energy because they are quickly converted into glucose, the fuel that powers cellular respiration to produce ATP. Glucose enters glycolysis and is further processed through the TCA cycle and oxidative phosphorylation, yielding energy efficiently for immediate needs like muscle activity and brain function. While fats provide more energy per gram, they must be broken down more slowly and are used when energy demand is sustained or fasting occurs; proteins are mainly for growth and repair and only supply energy after other stores are used. Nucleic acids store genetic information, not usable energy in normal metabolism. Carbohydrates, made up of carbon, hydrogen, and oxygen in a readily metabolizable form, fit best as the major energy source.