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

The link between glycolysis,the Krebs cycle,and the $\beta$-oxidation of fatty acids/carbohydrate and fat metabolism is ...........

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

Discuss "The respiratory pathway is an amphibolic pathway".

Given below are two statements:
Statement $I$ - $A$ stepwise release of chemical bond energy facilitates the utilization of a relatively higher proportion of that energy in $ATP$ synthesis.
Statement $II$ - Due to stepwise oxidation of respiratory substrate,the same pathway may be used for synthesis of another biomolecule.
In light of above statements,select the correct answer from the options given below.

The $Cori$ cycle is not found in muscles required for contraction at a slow pace and for a prolonged duration. Which organs does the $Cori$ cycle involve?