A biochemist is analyzing an aqueous solution of a pure unidentified macromolecule that she isolated from the cytosolic fraction of plant cells. After adding an enzyme that catalyzes the breaking of phosphodiester bonds, she observes that the macromolecule disappears. What is the most likely explanation?
a) The macromolecule is a protein.
b) The macromolecule is a lipid.
c) The macromolecule is a carbohydrate.
d) The macromolecule is a nucleic acid.