What specifically is glucose used for, and how is it broken down during digestion?

Glucose is a carbohydrate, and is the most important simple sugar in human metabolism. Glucose is called a simple sugar because it is one of the smallest units which has the characteristics of this class of carbohydrates. Glucose is also sometimes called dextrose. Corn syrup is primarily glucose. Sugars are digested and absorbed to provide your body with its greatest source of energy. During digestion, complex sugars are broken down and absorbed into the bloodstream. The simplest sugars, include glucose, galactose and fructose. Digestion occurs in the mouth, stomach and intestine.

The answer is observations and interpreting.