When comparing the subunits of the major organic macromolecules, it can be said that,

a. The reactive atoms that are covalently bound together via condensation always have the same components.
b. The disassembly of macromolecules into the subunits requires energy.
c. The subunits can be interchanged between the macromolecule types.
d. All subunits have the exact same elements in their core components.
e. Assembled subunits forming macromolecules have important non-covalent interactions within themselves and other macromolecules.