The three families of cellular macromolecules are polymerized and depolymerized by a general mechanism involving water. Each of them has a set of monomers whose polymerization changes the total free energy of the system. Which of the following statements is true regarding these macromolecules?

A) Each polymerization step requires free-energy input and proceeds by the consumption of one water molecule.
B) Each depolymerization step requires free-energy input and proceeds by the consumption of one water molecule.
C) Each polymerization step requires free-energy input and proceeds by the release of one water molecule.
D) Each depolymerization step requires free-energy input and proceeds by the release of one water molecule.