Could your weight affect how well your flu vaccine works? Is too much sparkling water bad for you? Why does head hair lose colour as you age, but other body hair doesn't? Why do spaceships have to travel so fast in the Earth's atmosphere? Is there a link between some vaccinations and autism? Why has there been a rise in fake news? And itching - what causes it and why does it sometimes seem to wander round your body? Plus, implanting magnets in the eye to help with nystagmus - so-called dancing eyes. Chris Smith answers your questions with Eusebius McKaiser on South Africa's Talk Radio 702...