Answer : 1. "Proteins"
Explanation :

Answer: A) Proteins Explanation: Here the Nitrogenous Food is Proteins. Nitrogenous Food :: The animal body is more than a machine. It requires fuel to enable it not only to work but also to live, even without working. A part of the food eaten must go to maintain the body Nitrogenous food compounds are sometimes classed together under the name of proteins. These may be divided into proteids, gelatinoids, and extractives.