We have dendritic cells and mass cells which are part of the innate immune system. And we have the T lymphocytes and the B lymphocytes as well as basic films and he hasn't phils. And in fact, the B lymphocytes and T lymphocytes can even further differentiate into other cells. So the B lymphocytes produce the plasma cells and the memory B cells T lymphocytes produce the helper T cells, the memory T cells, cytotoxic T cells and so forth. So this process by which a single stem cell somehow divides and produces these specialized cells that carry out a special type of function and eventually organize themselves into this conglomerate these structures we call organs that carry out highly specific and complex functions. This process is known as cell differentiation.