Carbohydrates are more easily metabolized than lipids. However, on a gram-for-gram basis, lipids provide cells with more-] A, nitrogen.
B. proteins.
C. structure.
D. energy.

Energy

Explanation: On a gram for gram basis lipids have the highest energy yield of all the food sources. They yield 9 kcal of energy per gram while carbohydrates and proteins yield only 4 kcal of energy per gram.

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the scientific method.