Human skin is composed of many layers of epithelial cells. The innermost layer of cells is composed entirely of stem cells while the outer layers are differentiated. A stem cell divides to produce two cells, one of which remains a stem cell and the other differentiates to become a mature skin cell. Hypothesize a scenario that could occur inside a skin stem cell that would cause only one of the two cells produced by division of the stem cell to differentiate. Include what's going on at the level of DNA, RNA, and proteins that makes the cell differentiated.
You do not need to learn all about how skin cells operate to answer this problem. Consider the skin stem cell to be similar to other stem cells and prepare a generic argument (make it up) about how stem cells can produce one differentiated cell and one cell that remains a stem cell.