What is the primary function of protein in the body?

The primary function of protein in the body is to build and maintain body tissue. Proteins are essential macromolecules composed of amino acids, which are the building blocks for the body's cells and tissues. They play a crucial role in muscle development, repair of tissues, and the production of enzymes and hormones. Without adequate protein intake, the body may struggle to repair tissues, recover from injuries, and maintain muscle mass.

Other options may suggest different functions, but they do not accurately reflect the core role of protein. For instance, while some foods containing protein can indeed provide energy, proteins themselves are not primarily stored for energy; that role is more directly associated with carbohydrates and fats. The assertion that proteins aid in digestion is specific to certain proteins like enzymes, but doesn't encompass the broad and primary role proteins play overall. Finally, the idea that proteins cool the body down is incorrect, as this is primarily managed by processes involving water and thermoregulation, rather than the action of proteins. Thus, the emphasis on protein’s role in building and maintaining body tissue accurately conveys its fundamental importance in human biology.