When acting as a respiratory substrate,which of the following would be broken down to acetyl Co-$A$?

Which of the metabolites is common to respiration mediated breakdown of fats,carbohydrates and proteins?

Which of the following biological molecules is common in the respiratory breakdown of fats,carbohydrates,and proteins?

What substances are transported by $Xylem$ and $Phloem$ respectively?

$A-$ Breaking down processes within the living organism is anabolism and synthesis is catabolism.
$R-$ The proteins would be degraded by proteases and the individual amino acids (after deamination) depending on their structure would enter the pathway at some stage within the Kreb's cycle or even as pyruvate or acetyl $CoA$.

Which of the following biomolecules is common to respiration-mediated breakdown of fats,carbohydrates,and proteins?