Answer:
Proteins
Step-by-step explanation:
There are four major biomolecules found in living system namely; proteins, carbohydrates, lipids and nucleic acids. These biomolecules serve different and unique functions in the body. PROTEIN is a biomolecule that helps in the break down of food substances in the body as stated in this question.
Specifically, these function of breaking down food substances is carried out by ENZYMES, which are biological catalysts that are proteinous in nature i.e. structurally made of proteins. For example, amylase enzyme breaks down starch, lipases break down lipids. Hence, since enzymes that perform this disintegration function are PROTEINOUS, then PROTEINS are the biomolecules that perform the role.