A double sugar molecule made of two monosaccharides bonded together through dehydration synthesis.

• A. Carbohydrate
• B. Monosaccharide
• C. Disaccharide
• D. Element

Answer: (C)

When two monosaccharides join by dehydration synthesis, they form a disaccharide, a double sugar. In dehydration synthesis a water molecule is removed as the two sugar units bond together through a glycosidic linkage, creating a covalent connection between them. A disaccharide is specifically two sugar units linked together, which is why it fits the description of a double sugar. Carbohydrate is the broad category that includes monosaccharides, disaccharides, and polysaccharides, but doesn’t specify the number of sugar units. A monosaccharide is a single sugar unit, not two. An element is not a molecule at all. Examples of disaccharides include sucrose, lactose, and maltose, which all illustrate two monosaccharide units bonded together.