Cells of tracheary elements (trcheids and vessels) become dead at maturity and lose their protoplasm due to the deposition of lignocellulosic cell wall thickenings. This is an example of

Options

A. growth
B. differentiation
C. dedifferentitation
D. redifferentiation

Explanation

To solve the question regarding the cells of tracheary elements (tracheids and vessels) becoming dead at maturity and losing their protoplasm due to the deposition of lignocellulosic cell wall thickenings, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Tracheary Elements**:
- Tracheary elements include tracheids and vessels, which are specialized cells in vascular plants responsible for the conduction of water and minerals.

2. **Maturation of Tracheary Elements**:
- At maturity, these cells undergo significant changes. They lose their protoplasm, which means they become devoid of living cellular contents.

3. **Lignocellulosic Cell Wall Thickening**:
- The thickening of the cell walls is primarily due to the deposition of lignin and cellulose, which provides structural support and rigidity.

4. **Cell Differentiation**:
- The process by which these cells undergo changes in structure and function is known as cell differentiation. During this phase, cells specialize and develop specific features that enable them to perform their functions effectively.

5. **Conclusion**:
- Therefore, the example given in the question, where tracheary elements become dead at maturity and lose their protoplasm due to lignocellulosic thickening, is an example of **cell differentiation**.

### Final Answer:
This is an example of **cell differentiation**.