The process by which cells develop unique characteristics in structure and function is called cell differentiation.

Here's a breakdown:

* Differentiation: This refers to the process where a less specialized cell becomes more specialized, acquiring specific features and functions.

* Structure: This refers to the physical form and organization of a cell, including its shape, size, and internal components.

* Function: This refers to the specific role or task a cell performs within an organism.

Example: A stem cell, which is unspecialized, can differentiate into a muscle cell, a nerve cell, or a blood cell. Each of these cell types has a unique structure and function.

Let me know if you'd like more details on cell differentiation or specific types of cells!