Which type of carbohydrate consists of long chains of monosaccharide units linked together?

Polysaccharides are indeed the type of carbohydrate that consists of long chains of monosaccharide units linked together. These chains can be highly branched or unbranched and can vary significantly in terms of the number of monosaccharide units they contain. Common examples of polysaccharides include starch, cellulose, and glycogen.

Monosaccharides, on the other hand, are the simplest form of carbohydrates and consist of single sugar units, such as glucose and fructose. Disaccharides consist of two monosaccharide units linked together, like sucrose (table sugar) and lactose (milk sugar). The term saccharides is a broader category that includes all types of carbohydrates, both simple and complex. However, it does not specifically refer to the long chains characteristic of polysaccharides. Therefore, the defining feature of polysaccharides makes them the correct choice in this context.