Answer: Glucose is a common example of monosaccharide, as well as fructose, and galactose.
Explanation: The reason why glucose is an example of a monosaccharide is because, as stated like in your definition, glucose is a single sugar molecule that has a ratio of 1:2:1 (C:H:O). Glucose's chemical formula is C₆H₁₂O₆. Cellulose, the other answer, is NOT a monosaccharide. It is a polysaccharide, as it consists of many monosaccharides.
