Three important questions on humanity

The first things which comes to my mind whenever i encounter the word Humanity it have something to do with us-the humans. Though my first questions would be, 1. How comes humans have different behavior some are good and some are evil minded? 2. Why some humans are filthy rich and other are living below poverty? 3. Why the distribution of properties is not fairly given to the welfare of the common goods? I do hope the speaker could explain me briefly about those reasons in a logical manner that even those with below average reasoning could deeply understand his replies on my questions using analytic, critical, or speculative methods.