Explain in $2-3$ lines each of the following terms with the help of examples taken from different plant tissues.
$(a)$ Differentiation
$(b)$ De-differentiation
$(c)$ Re-differentiation

(N/A) Differentiation: Cells derived from the root apical and shoot apical meristem and cambium mature to perform specific functions. This process is termed as differentiation. During this,cells undergo major structural changes in their cell walls and protoplasm.
Example: To form a tracheary element,cells lose their protoplasm and develop strong,elastic,lignocellulosic secondary cell walls to transport water.
De-differentiation: Living differentiated cells that have lost the capacity to divide can regain the ability to divide under certain conditions. This phenomenon is termed as de-differentiation.
Example: Formation of interfascicular cambium and cork cambium from fully differentiated parenchyma cells.
Re-differentiation: The cells produced by de-differentiated meristems once again lose the capacity to divide but mature to perform specific functions. This is called re-differentiation.
Example: Formation of secondary xylem and secondary cortex.