Onions are one of the most versatile root vegetables around. Onions grow in the ground and are made up of various layers, which are important to identify when cooking. At the center, onions have a fan of green leaves. Out of this fan, a series of bulb scales starts to grow as the plant matures. These scales are commonly known as the layers. The onion has a protective thin outer covering known as the tunic or skin. The tunic covers the fleshy layers, which are the ones commonly used for cooking.

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