Glucose is most critical as an energy source for which of the following organs?

• A. Heart
• B. Brain
• C. Liver
• D. Kidneys

Answer: (B)

Verified step by step guidance

1. Understand that glucose is a primary energy source for many organs in the body, but some organs are more dependent on it than others.
2. Recognize that the brain is highly dependent on glucose as its main energy source because it cannot store glucose and relies on a constant supply from the bloodstream.
3. Consider the heart, liver, and kidneys: while they use glucose, they can also utilize other energy sources like fatty acids and ketone bodies.
4. Note that during periods of fasting or low glucose availability, the brain can adapt to use ketone bodies, but it still primarily relies on glucose under normal conditions.
5. Conclude that the brain's reliance on glucose is more critical compared to the heart, liver, and kidneys, making it the correct answer.