Why don't eyebrows go grey?

Why aren't bubbles coloured like the soap they came from? Does holding a remote control to you head make it work better? Why has exercise reduced my alcohol tolerance? Is it by design that the names of all continents start and finish with the same letter? Why don't eyebrows go grey at the same time as head-hair? Do things taste different on opposite sides of the mouth? Why remove metal objects before a medical scan? And why does running water make me want to wee? Join Dr Chris for the answers to this week's questions as well as news of a way to correct mitochondrial enzyme defects...