Answer;
Because the stimuli to bring about mitosis are lacking
Explanation;
-Cell differentiation is the process whereby a cell becomes more specialized in terms of structure and function as in the case of a liver cell, a blood cell, or a neuron.
-Undifferentiated are the cells that have not yet become specialized, so these cells could still become any kind of cell that the body needs. Different tissues have different kinds of organisms inside the cells. Differentiation occurs many times during the development of a multicellular organism.
-Mitosis is a type of cell division by binary fission (splitting in two) which occurs in certain eukaryotic cells. Mitosis generates new body cells (somatocytes) for renewal and repair.