What term describes a simple sugar that serves as a primary energy source?

• A. Fructose
• B. Glucose
• C. Lactose
• D. Maltose

Answer: (B)

Glucose is the simple sugar that serves as the body's main energy source. It’s a single sugar unit that is quickly absorbed into the bloodstream and then used by cells to produce ATP through glycolysis and cellular respiration. This makes glucose the primary fuel for most tissues, including the brain, which relies heavily on it for energy. Other sugars like fructose, lactose, and maltose are different types of sugars with distinct roles: fructose is processed mainly in the liver, lactose is milk sugar made of glucose and galactose, and maltose is two glucose units. They can provide energy too, but glucose best fits the description of a simple sugar that serves as the primary energy source.