WAEC Biology 2013 Papers

Concept:Different food classes release different amounts of energy per gram, and water supplies no energy.Explanation:For the same quantity of food, fats and oils provide the highest energy value, about $9\ \text{kcal/g}$.Carbohydrates and protein each provide about $4\ \text{kcal/g}$.Water provides no usable energy to animals.Therefore, the descending order of energy value is:Fats and oils $>$ Carbohydrates $>$ Protein $>$ Water.This order matches option B.Answer:B. Fats and oils, carbohydrates, protein, water