What is the primary storage form of carbohydrates in the human body?

Glycogen is indeed the primary storage form of carbohydrates in the human body. It is a polysaccharide that serves as a crucial energy reserve, primarily found in the liver and muscle tissues. When the body has an excess of glucose, it converts this glucose into glycogen through a process called glycogenesis. This stored glycogen can later be broken down into glucose when energy is needed, especially during periods of fasting or intense physical activity.

In contrast, glucose itself is the simplest form of carbohydrate and serves primarily as an immediate energy source rather than a storage form. Starch, while a storage form of carbohydrates in plants, does not play a significant role in human carbohydrate storage. Fiber is a non-digestible carbohydrate that contributes to digestive health but is not stored for energy. Thus, glycogen stands out as the correct answer due to its essential role in carbohydrate metabolism and energy storage in the human body.