Among the following carbohydrates, which one is correctly classified as a polysaccharide?

Introduction / Context:
Carbohydrates are broadly divided into monosaccharides, disaccharides and polysaccharides based on the number of simple sugar units they contain. Understanding these categories is important in both biology and chemistry because structure strongly influences function. This question asks you to identify which of the listed substances is a polysaccharide, that is, a carbohydrate made from many repeating sugar units joined together.

Given Data / Assumptions:

• Fructose, glucose and galactose are common simple sugars.
• Sucrose is a common table sugar formed by combining two monosaccharides.
• Cellulose is a structural component of plant cell walls.
• We assume knowledge of basic carbohydrate classification.

Concept / Approach:
Monosaccharides are the simplest carbohydrates, such as glucose, fructose and galactose, and contain a single sugar unit. Disaccharides, such as sucrose, lactose and maltose, contain two sugar units. Polysaccharides are long chain carbohydrates made up of many monosaccharide units linked together and include substances like starch, glycogen and cellulose. Cellulose is a major structural polysaccharide in plants and is composed of many glucose units linked by specific glycosidic bonds. Therefore, among the options, cellulose is the polysaccharide.

Step-by-Step Solution:
Step 1: Classify fructose as a monosaccharide because it contains just one simple sugar unit. Step 2: Classify glucose as another monosaccharide, widely used as an energy source in cells. Step 3: Recognise sucrose as a disaccharide formed from glucose and fructose units. Step 4: Recall that cellulose is a polymer made from many glucose units and serves as a plant structural material. Step 5: Conclude that cellulose is the only polysaccharide among the given options.

Verification / Alternative check:
If you consult a typical classification table, you will see that monosaccharides include glucose, fructose and galactose, disaccharides include sucrose and lactose, and polysaccharides include starch, glycogen and cellulose. Cellulose consistently appears under the polysaccharide category. No standard reference lists fructose, glucose or sucrose as polysaccharides, because they contain only one or two sugar units. This cross check confirms the identification of cellulose as the correct answer.

Why Other Options Are Wrong:
Fructose is a single sugar unit and therefore a monosaccharide, not a polysaccharide.
Glucose is also a monosaccharide, widely important for energy metabolism, but it is not a polymer of many sugars.
Sucrose is composed of two monosaccharide units, glucose and fructose, so it is classified as a disaccharide.
Galactose, similar to glucose and fructose, is a monosaccharide and does not meet the definition of a polysaccharide.

Common Pitfalls:
Some students may confuse sugar types because several names sound similar or because they are all common in the diet. Remember that the key to identifying a polysaccharide is the presence of many repeated sugar units, not just one or two. Linking each name to a typical example or function can help: glucose for energy, sucrose as table sugar and cellulose as plant fibre. Using these associations makes it easier to place each carbohydrate into the correct category.

Final Answer:
The carbohydrate that is correctly classified as a polysaccharide is cellulose.