Answer:
Molecule
Step-by-step explanation:
A molecule is the smallest particle of sugar (glucose - C6H12O6) or any other substance because a molecule possess all properties of that particular substance.
Molecules are responsible for all the chemical and physical properties of a substance, so molecules decided the properties of sugar as well. If the molecule will be broken, it will lose its properties. Sugar is composed of molecules that include 6 atoms of carbon, 12 atoms of hydrogen, and 6 atoms of oxygen.
Hence, the correct answer is "Molecule".