Which of the following monosaccharides is an important source of energy in living organisms?

Explanation

Glucose is the primary fuel molecule for cellular respiration in most living things. Cells break down glucose to release energy stored in its chemical bonds.

Your body converts most carbohydrates you eat into glucose. Blood carries glucose to cells throughout your body where it powers all life processes.

While fructose also provides energy, glucose is more directly used by cells. Ribose and deoxyribose are structural sugars in DNA and RNA, not primary energy sources.