Risk Versus Return in a Portfolio

Dr. harry markitz looked at the correlation between risk and returns in a portfolio. The one that went up, just for people that don't know what's ex in, what's why? He had two axes. So so on the bottom, low return s. On the top are high returns. And then left for the left right axis, the x x. That thais, i love continuing this cause it bothers the hell ot a pallit.