Final answer:
Rice is the world's chief source of food carbohydrate, containing the highest percentage of starch compared to other crops like potatoes, wheat, and corn.
Step-by-step explanation:
According to research, the world's chief source of food carbohydrate is rice. It is considered a staple food in many countries and provides a significant amount of dietary carbohydrates. Other crops such as potatoes, wheat, and corn also contain carbohydrates, but rice has the highest percentage of starch among them (75%).