The leaf bases of onion contain ______ tissues.

Explanation

**Step-by-Step Solution:**

1. **Identify the Structure**: The question asks about the leaf bases of onions. We need to understand what part of the onion we are discussing.

2. **Understand the Function**: The leaf base connects the leaf to the stem. It serves as a junction between these two structures.

3. **Identify the Tissue Type**: The leaf base contains a specific type of tissue that is responsible for growth in the middle portion of the plant. This type of tissue is known as meristematic tissue.

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