Chris Smith from The Naked Scientists takes on YOUR questions with Africa Melanie from CapeTalk. Why can only some animals be domesticated? Why do cats purr? Can senses change after surgery? Why don't I have a runny nose during sleep? How old is moon dust? Why do scars last until old age? Plus scientists detect a black hole that's munching on a neutron star... For more podcasts by The Naked Scientists, head to nakedscientists.com/podcasts.PLUS, you can follow the team on Instagram, Twitter and Facebook; @nakedscientists. Like this podcast? Please help us by supporting the Naked Scientists