cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. this process is
controlled by

c) gene expression

Explanation:

Specialized cell refers to a differentiated cell which which performs specific function in the body. For example, RBC helps in transportation of oxygen and carbon dioxide in the body, nerve cell helps in transmission of electrochemical signals throughout the body et cetera.

Undifferentiated cell becomes specialized cell through gene expression.

Each cell in the body contains same genes; however, a particular set of gene is expressed in particular type of cell.

Consequently, different sets of proteins are formed which leads to formation of different types of cells.

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