The organic molecule called is formed of branched chains of sugar units. it is used by humans (and other mammals) to store carbohydrate in the liver and skeletal muscle.

Answer;

-Glycogen

The organic molecule called glycogen is formed of branched chains of sugar units.

Explanation;

-Glycogen is a branched polysaccharide of glucose that serves as a form of energy storage in humans, animals, fungi, and bacteria.

-In humans, glycogen is made and stored in liver and muscle cells. Muscle cell glycogen is broken down into glucose, and liver glycogen is broken down into glucose as a circulating energy source glucose for use by the body.

-Glycogen is accumulated in response to insulin and broken down into glucose in response to glucagon. It plays a major role in maintaining the blood-glucose levels, which is vital since some organs in the body such as the brain purely depend on glucose for energy.