Which of the following molecules are primarily used as energy sources by living organisms?

• A. Cholesterol
• B. $\mathrm{Glucose}$
• C. $\mathrm{Cellulose}$
• D. $\mathrm{Nucleic} \mathrm{acids}$

Answer: (B)

Verified step by step guidance

1. Identify the primary function of each molecule listed: Cholesterol, Glucose, Cellulose, and Nucleic acids.
2. Understand that energy sources for living organisms are typically molecules that can be metabolized to release energy.
3. Recognize that glucose is a simple sugar and a primary energy source for cells through processes like glycolysis and cellular respiration.
4. Consider the role of cellulose, which is a polysaccharide used for structural purposes in plants and not directly used for energy by most organisms.
5. Acknowledge that nucleic acids are involved in genetic information storage and transfer, not as a primary energy source.