What is the nutritional role of proteins in the body?

The choice stating that proteins build and repair tissues accurately describes one of the primary functions of proteins in the body. Proteins are made up of amino acids, which are the building blocks necessary for the growth and maintenance of all body tissues. This includes muscle tissue, as well as skin, hair, and organs. When the body undergoes stress, such as injury or illness, proteins play a crucial role in repair and recovery processes. Additionally, proteins contribute to the structure of enzymes, hormones, and other important biological molecules, reinforcing their essential role in maintaining and enhancing bodily functions.

The other options, while they describe important bodily functions, do not pertain specifically to the role of proteins. Storing energy is primarily the function of carbohydrates and fats. Regulating body temperature is managed through various physiological processes, primarily involving the skin and circulatory system. Promoting metabolic reactions is largely the role of enzymes, which are proteins but involve a broader scope of metabolic processes beyond just tissue building and repair.