What is the main function of glycogen in animals?

The primary function of glycogen in animals is energy storage. Glycogen is a polysaccharide that serves as a form of stored glucose, which is a crucial source of energy. When the body requires glucose for metabolic processes—such as during exercise or between meals—the glycogen stored in the liver and muscles is broken down into glucose molecules through a process called glycogenolysis. This quick release of glucose helps maintain blood sugar levels and provides energy to various tissues and organs.

In particular, the liver regulates blood glucose levels by releasing glucose into the bloodstream when needed, while muscle glycogen is primarily utilized for energy during physical activity. This dual role allows animals to efficiently manage energy resources and respond to varying energy demands.

The other answer choices do not reflect the primary role of glycogen. Structural support is typically provided by proteins or polysaccharides like cellulose in plants. Cell communication is more closely associated with signaling molecules and receptors rather than glycogen. DNA storage is the function of nucleic acids, not glycogen, which does not play a role in storing genetic material. Thus, glycogen's main function as an energy storage molecule is essential for the overall energy management in animal physiology.