Final answer:
Creaming requires solid fat to incorporate air and create a light and fluffy texture in baked goods. Vegetable oils, being liquid, cannot trap air in the same way as solid fats, resulting in a different texture in the final product.
Step-by-step explanation:
We cannot use vegetable oil for creaming because vegetable oils are liquid at room temperature and do not have the necessary structure to create the desired texture in creaming. Creaming is a technique in baking where solid fat, such as butter or margarine, is beaten together with sugar to incorporate air and create a light and fluffy texture in baked goods. Vegetable oils, being liquid, cannot trap air in the same way as solid fats, leading to a different texture in the final product.