What are respiratory substrates? Name the most common respiratory substrate.

(N/A) Respiratory substrates are the organic compounds that are oxidized during the process of cellular respiration to release energy in the form of $ATP$.
$1$. The most common respiratory substrate is $Glucose$ (a carbohydrate).
$2$. Other substances like fats, proteins, and organic acids can also act as respiratory substrates depending on the metabolic requirements of the cell.