Describe structure of a tracheid.

Explanation

**Step-by-Step Text Solution:**

1. **Definition and Location**: Tracheids are specialized cells found in the xylem, which is the vascular tissue responsible for water and nutrient transport in plants. They are present in all vascular plants.

2. **Shape and Structure**: A tracheid is a highly elongated, tube-like cell. This shape allows for efficient water transport.

3. **Cell Walls**: The walls of tracheids are hard, thick, and lignified. Lignification provides strength and rigidity, which is essential for supporting the plant structure.

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