Which of the following provide the most readily available energy?
a. carbohydrates
b. lipids
c. nucleic acids
d. proteins

The answer is a. carbohydrates. The amount of potential energy in the molecule depends on the number of C-H bonds in the molecule. Carbohydrates have more C-H bonds. Thus, they can serve as energy storage. Other macromolecules have less C-H bonds. Thus, when energy is needed immediately, complex carbohydrates break down to simple carbohydrates and the energy is released.