What is the main storage form of glucose in humans?

Glycogen is the main storage form of glucose in humans. It is a polysaccharide that serves as a crucial energy reserve, primarily found in the liver and muscles. When the body requires glucose, glycogen can be rapidly mobilized and converted back into glucose through a process called glycogenolysis. This is particularly important during periods of fasting or intense exercise when quick access to energy is needed.

In the liver, glycogen helps maintain blood glucose levels, while in muscle tissue, it provides a local energy source for muscle contractions. The structure of glycogen allows for efficient storage and quick release, making it an ideal form of energy storage for short-term demands.

Starch, on the other hand, is the primary storage form of glucose in plants and not predominantly found in humans. While glucose itself is a simple sugar that provides immediate energy, it is not stored in significant amounts. Fructose is another type of sugar that can be metabolized for energy but does not serve as a primary storage form of glucose. Thus, glycogen stands out as the correct answer in the context of glucose storage in humans.