What is an example of a macro-nutrient?

A macro-nutrient refers to nutrients that are required in large amounts by the body to provide energy and facilitate various physiological functions. Proteins, carbohydrates, and fats are the three primary categories of macro-nutrients. In this context, protein plays a crucial role; it is vital for building and repairing tissues, producing enzymes and hormones, and supporting overall immune function. The body breaks down proteins into amino acids, which are essential for growth and maintenance.

On the other hand, the other options—Vitamin C, calcium, and iron—are classified as micro-nutrients. These micro-nutrients are required in smaller amounts but are still essential for health, contributing to various bodily processes such as immune function (Vitamin C), bone health (calcium), and oxygen transport (iron). While they are important, they do not provide the energy needed by the body in the same way that macro-nutrients like protein do. This distinction makes protein the correct answer in the context of identifying a macro-nutrient.