Cellular respiration is the process<span> by which the chemical </span>energy<span> of "food" </span>molecules<span>is </span>released and partially captured in the form of ATP. <span>Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways </span>involved<span>.</span>
People had asked this many times and that is why they came up with methods and standards that will answer these type of questions. You can look it up in the NIST or the National Institute for Standards and Technology.