The formula also means each type of cells has at least one regulatory sequence. The average number is k 3 . The quantities of each type of cells are controlled by the number of times this type of cells is generated. The more the quantity, the more the times this type of cells is generated. The quantity of cells generated each time is not directly determined by DNA information, but by the cellular feedback signals. It is the times of generating that determines the quantities of each type of cells.