What is a large molecule composed of many linked monosaccharides called?

A large molecule composed of many linked monosaccharides is called glycogen. Glycogen serves as a storage form of glucose in animals and is a polysaccharide, which means it is made up of numerous monosaccharide units (specifically glucose) linked together. This complex structure allows for efficient energy storage and rapid mobilization when glucose is needed by the body.

The other choices listed do not pertain to linked monosaccharides. For instance, proteins are composed of amino acids rather than monosaccharides, and polypeptides are specific sequences of amino acids forming a protein, not carbohydrates. Cholesterol is a type of lipid and is not a polymer of monosaccharides but rather a steroid molecule. Therefore, glycogen is the correct answer as it directly relates to the composition of many linked monosaccharides.