In which form does the body store carbohydrates?

The body stores carbohydrates primarily in the form of glycogen. Glycogen is a large, branched polymer of glucose molecules that serves as a readily accessible energy reserve for the body, particularly in the liver and muscles. When the body needs a quick source of energy, glycogen can be quickly broken down into glucose and released into the bloodstream.

While glucose is the primary sugar that circulates in the bloodstream, it is not the storage form of carbohydrates within the body. Fructose, another type of sugar, is found in fruits and is metabolized differently, but it is not a storage form of carbohydrates. Starch, on the other hand, is a polysaccharide that plants use to store energy, but it is not directly involved in human carbohydrate storage. Instead, humans convert starch from the diet into glucose, which can then be stored as glycogen. Thus, glycogen is the key molecule for carbohydrate storage in the body, making it the correct answer.