Answer: Yogurt and walnut
Explanation:
Yogurt and walnut combined cannot be used as a source of 20 amino acids as yogurt is rich in protein but walnut is rich in fat. It does not contain any amino acid and is rich in vitamins and minerals.
A complete protein rich diet is a diet which includes all the 20 amino acids in it. The amino acid lacking in one food is compensated by another food.
But here, in a combination of yogurt and amino acids the yogurt is a rich source of protein but walnut is a rich source of fat only.
