Which of the Following Characterizes a DIFFERENCE Involved in the De

Which of the following characterizes a DIFFERENCE involved in the de novo biosynthesis of purines and pyrimidines?

A) Pentose phosphate is added before completion of a heterocyclic ring system in one case, and not the other.
B) One heterocyclic ring system is synthesized from low molecular weight precursors, the other is not.
C) The synthesis of one ring system involves the use of ATP as an energy source, the other does not.
D) Asparagine is a precursor in one case, and not the other.
E) The amino group of glutamate is an immediate precursor in the synthesis of one ring system, and not the other.