Final answer:
The pineapple was the food unknown to the Old World before the 1500s. The Columbian Exchange introduced it, along with other crops like corn and potatoes, to Europe, Africa, and Asia, while the Old World brought crops such as wheat and onions to the Americas.
Step-by-step explanation:
The Origin of Foods in the Old World
The food that was unknown to the Old World before the 1500s out of the list provided is the pineapple. Foods like watermelon, peaches, eggplant, and ginger were known in the Old World before the Columbian Exchange. The Columbian Exchange drastically altered global agriculture, introducing a variety of new crops to Europe, Africa, and Asia from the Americas, such as maize (corn), potatoes, tomatoes, and pineapples, while bringing crops like wheat, onions, and coffee beans to the New World.
Indeed, the tomato-based sauces that are a staple in Italian cuisine today only became possible after the tomato was brought to Europe in the 1500s. Similarly, the potato, which now serves as a fundamental component in many European diets, was not introduced to Europe until the 1500s. These new foods played significant roles in altering diets and contributing to population growth and technological advancements.