Adam Rutherford talks to neuroscientist Molly Crockett about moral decision-making in the brain. She combined brain scanning with a test involving money and electric shocks. Geoff Marsh reports from Japan where stem cell research appears to be bringing regenerative medicine for a common cause of blindness ever closer. A team at the Max Planck Institute for Evolutionary Anthropology has pulled off another triumph in the study of ancient human DNA. Viviane Slon explains how they've extracted DNA of extinct species of humans from the soil in caves across Europe and Russia. Adam discusses the significance with Ian Barnes, ancient DNA specialist at the Natural History Museum in London. Dan Friess of the National University of Singapore studies mangrove forests around the coasts of tropical Pacific and Indian ocean countries. This kind of forest has turned out to store much more carbon than even rainforests, as measured by the hectare. Dr Friess talks about carbon counting in mangroves and how this research may save the forests from further destruction.