What food group is a primary source of protein?

The primary source of protein includes meat, poultry, fish, eggs, beans, and legumes. These foods contain high-quality protein that is essential for various bodily functions such as muscle building, repair, and maintenance. Proteins are made up of amino acids, some of which are essential and must be obtained through diet. The inclusion of a variety of these protein sources in the diet contributes to overall health, as they provide vital nutrients beyond protein, such as vitamins and minerals.

While dairy is a good source of protein, it is not as comprehensive in terms of variety and options as meat, poultry, fish, eggs, and legumes. Fruits generally contain very little protein and are more focused on providing vitamins, minerals, and carbohydrates. Grains also provide some protein, but typically in lower amounts compared to the higher protein density found in the options listed under the correct answer. Thus, the group that encompasses all these protein-rich foods is the most comprehensive answer.