Final answer:
Differentiation is the process in which unspecialized cells become specialized to perform distinct functions in the body.
Step-by-step explanation:
Differentiation is the process in which unspecialized cells become specialized to perform distinct functions in the body. During this process, cells undergo major changes in size, shape, metabolic activity, and overall function. This allows different cell types to express specific portions of their DNA that are relevant to their function, resulting in unique genetic expression for each cell type.