Answer:
Differential gene expression
Explanation:
1. Cell specialization occurs due to the differential gene expression, it is the process which is responsible for the production of cells with different traits at different positions and at different time. This process changes cells from simple to more specialized in both structure as well as in function. This is all due to the differential gene expression where all cells beside containing the same gene, express different genes in different cells.
2. Cell differentiation is very important among almost all multicellular organisms. This process results in the formation of a complex organism with different types of tissues and cells from a zygote.