Final answer:
Biological macromolecules are considered organic because they contain carbon-hydrogen bonds and carbon is the fundamental component of these macromolecules. Carbon atoms can form covalent bonds with multiple atoms, making it the ideal structural component for macromolecules.
Step-by-step explanation:
Biological macromolecules are considered organic because they contain carbon-hydrogen bonds. Carbon is the fundamental component of these macromolecules and it has unique properties that allow it to form covalent bonds with up to four different atoms, making it the ideal backbone for the macromolecules.
In addition to carbon, biological macromolecules may also contain hydrogen, oxygen, nitrogen, and other minor elements.