Answer:
Used as the primary source of energy in living organisms
Explanation:
Proteins are the main structural and functional molecules of the body. They make up hormones that are used in signaling, make up the structure of cells, immunoglobulins, carrier proteins, and etcetera. However, the main energy source of the cells is glucose (sourced from carbohydrates). Protein is metabolized as the last resort after glucose and fats. This is because protein breakdown has toxic nitrogenous byproducts (such as creatinine, ammonia, and urea) due to their amino group.
