Which of the following foods is an excellent source of complete protein?

The selection of chicken as an excellent source of complete protein is based on its amino acid profile. Complete proteins contain all nine essential amino acids that the body cannot produce on its own, making them crucial for various bodily functions, including building and repairing tissues, hormone production, and immune function.

Chicken is particularly rich in these essential amino acids, which makes it a high-quality protein source. It's widely included in diets for its effectiveness in supporting muscle growth and maintenance, especially in active individuals or those looking to improve their overall protein intake.

In contrast, while broccoli and quinoa also provide valuable nutrients, they do not contain the complete range of essential amino acids in proportions that would qualify them as a complete protein. Broccoli, as a vegetable, offers relatively lower protein content, and while quinoa is considered a complete protein among plant sources, it typically does not match the protein density found in animal sources like chicken. Pasta, primarily made from wheat, also lacks certain essential amino acids, making it an incomplete protein source. Thus, chicken stands out as the most readily available and effective complete protein source in this context.