Where does glycerol enter the respiratory pathway?

Which of the following substrates can enter into the respiration process?

Which of the following links carbohydrate and fat metabolism?

Given below are two statements:
Statement $I$ - Reactions involved in Krebs cycle are anabolic and catabolic.
Statement $II$ - During oxidation of acetyl $CoA$,stepwise oxidation of the acetyl part of acetyl $CoA$ occurs.
In light of the above statements,choose the most appropriate answer from the options given below.

During prolonged fasting,which of the following is the correct order of utilization of energy sources in the human body?

Protein cannot be used directly as a respiratory substrate; it breaks down into which of the following?