Which of the following is NOT a source of protein?

Potatoes are primarily a source of carbohydrates, specifically starch, and do not contain significant amounts of protein compared to the other options listed. While potatoes do have some protein content, it is relatively low and not enough to classify them as a primary source of protein. In contrast, meat, fish, and legumes are all rich sources of protein, essential for various bodily functions such as building and repairing tissues, making enzymes and hormones, and supporting overall health. Legumes, which include beans and lentils, are especially noted for being plant-based proteins that are critical in vegetarian and vegan diets.