So these four processes includes cell proliferation, cell growth, cell differentiation and morphogenesis. So let's begin with cell proliferation. So we know that we begin with a single zygote, a single cell. But eventually our body consists of billions of different cells. So what cell proliferation means is the zygote, to go from one cell to billions of cells must actually divide via mitosis and cytokinesis. So the single cell zygold undergoes mitosis and cytokinesis many, many times until it forms the billions of cells that are found in the adult human organism.