Which of the following describes polysaccharides?

Polysaccharides are a class of macromolecules that consist of long chains of monosaccharide units. Specifically, they are formed by the linkage of three or more monosaccharides through glycosidic bonds. This structure allows polysaccharides to serve various functions in living organisms, such as energy storage (as seen with starch in plants and glycogen in animals) and structural support (like cellulose in plant cell walls).

The correct answer highlights that polysaccharides are not limited to just two sugar molecules, which would classify them as disaccharides, nor are they single sugar units, which are classified as monosaccharides. Additionally, describing polysaccharides as consisting primarily of fatty acids refers to lipids rather than carbohydrates, underscoring the distinct classification of biological macromolecules. Thus, the correct choice accurately encompasses the definition and structure of polysaccharides in relation to their building blocks.