Why are there different types of cells in multicellular organisms?

All cells in our bodies contain the same precise DNA. But different cells have different functions. The shape and shape of a cell is most often dictated by its function. For example, a red blood cell must be very small to fit into the capillaries. As the organism develops, some stochastic process causes the cells to take one developmental path or the other, and then communicate with each other to maintain this commitment and ensure that there are enough different types of cells and their geometric relationship to each other.