Which of the following knife skills is useful for preparing ingredients for stir-frying?

The most relevant knife skill for preparing ingredients for stir-frying is chopping, as this technique allows for the quick and effective cutting of vegetables, meats, and other ingredients into uniform pieces. Stir-frying requires ingredients to be cut into bite-sized pieces that will cook evenly and rapidly in a hot pan. Chopping is especially important because it can produce pieces that are small enough to cook through quickly, preventing one ingredient from being undercooked while allowing others to become burnt.

While slicing and puréeing have their own specific uses in the kitchen, they are less suitable for the demands of stir-frying. Slicing might be used for certain foods that require thin cuts, but it does not provide the uniformity or size necessary for quick cooking in a stir-fry. Puréeing is not relevant at all in this context, as it involves blending ingredients into a smooth consistency, which is not suitable for stir-fried dishes where individual pieces should maintain structure and texture. Therefore, chopping is the most appropriate knife skill for preparing ingredients that will be stir-fried.