. >> "college, inc." watch frontline. >> and now, exclusively on-line., violent encounters between police and civilians. >> people were shot and killed by the new orleans police department. >> six controversial cases. >> there's no police report. they said something about a shoot-out. >> the times picayune, pro publica, fronltine and you uncover the truth. >> there are all these unanswered questions. >> an online investigation of "law and disorder" at pbs.org. >> next time on frontline world... in southern africa, it was supposed to harness the energy of children to bring fresh water to their villages. now, five years later... >> this play pump hasn't produced any water for six months. >> what went wrong with the play pump? >> we would all love there to be a magic bullet. that's not the way it works. >> the politics of trying to help. this story and more on the next frontline world. >> be more pbs. >> we will see why tornadoes form. >> my first reaction when i saw this mummy was, "oh, my god, it's a pharaoh." >> it is the key to curing disease. >> well,

inc. and scholars were are than they knew when they related skin color to climate. today's collegesconcur. sunny climates do make people dark skinned. and cold climates make people light-skinned. how much of which is sort of valid people have in this can and to what degree it is expressed deepened entirely over time on exposure to the sun's ultraviolet, or uv, radiation. melanin those protecting its excessive ultraviolet radiation and allows sufficient uv radiation to enter the body. too much uv radiation causes skin cancer, and can lead to death. and uv radiation is crucial for developing fetuses and strong bones. so where are we now? mapping the human genome elicited a initial proclamations of human candidness across the globe. then raced off described racial differences on our genes. that talk is not disappeared. but ideally we would realize that human beings short history relates us all to one another. to speak in racial terms, incessant human migration has made us all multiracial. does this mean the human genome or civil rights or desegregation have entered the tyranny of race