Which of the following foods are major sources of protein?

Meats and dairy products are recognized as major sources of protein because they contain high-quality proteins that provide all the essential amino acids needed for the body's functions. Proteins from these sources are generally considered complete proteins, as they furnish the necessary building blocks for muscle repair, hormone production, immune function, and overall growth.

Meat, including chicken, beef, pork, and fish, is not only rich in protein but also contains vital nutrients such as iron, zinc, and B vitamins. Dairy products, such as milk, cheese, and yogurt, also offer significant protein content along with calcium, which is crucial for bone health. The body's ability to utilize and absorb proteins from these foods effectively makes them vital components of a balanced diet, especially for individuals engaged in athletic training who require adequate protein intake to support recovery and muscle maintenance.

Other options, while they may contain some protein, typically do not provide the same level of amino acids and overall protein quality as meats and dairy. Fruits and vegetables generally have low protein content, grains contain varying amounts of protein but are often incomplete, and oils and fats do not contain protein at all.