No one seems to know why some of us can roll our tongues (into a tube shape) and some of us can't ! For years it has been thought that tongue rolling is genetically inherited. This means that if both your parents carry the gene and can roll their tongue, you have a 3 in 4 chance of being able to roll your tongue too. We don't know if there is an evolutionary advantage. It may be that if a gene involved in tongue rolling is close to another important gene, they may be inherited together. (Eg. People who have Cystic Fibrosis seem to have protection against salmonella, so there are lots of cystic fibrosis carriers in Europe). some scientists reckon you can learn to tongue roll with practice, but you need to carry the gene in order to succeed! However whether tongue rolling is genetically inherited at all, is now debated, as studies in 1975 in identical twins showed about 1/3 of them don't share the trait. So the long and the short of tongue rolling is we don't know - maybe tongue rolling was important in our ancestors for eating, drinking or speaking. A study in Spain showed 67% women and 64% men can roll their tongues, whilst another more recent internet survey suggested up to 81% people might be able to perform the feat.

Dying actually serves a useful purpose because it is one way to eliminate weaker individuals, and the genes that they carry, from the population. If you inherit a bad gene which makes you less healthy and causes you to die at a young age, there is a lower chance of passing that faulty gene on to your future offspring, removing the gene from the population so that it cannot harm any of your descendents. But for most people the simple answer to why we die is because of the process of ageing. But if you ask why do we age, the simple answer is we don't know. It would appear that our bodies do not repair themselves adequately to the extent that we slowly accumulate damage to our cells and our DNA which eventually claims our lives. What we do know about ageing and longevity is that the process is heavily influenced by the genes that you inherit from your parents - in other words, if members of your family tend to live a long time, then you will too. One way to increase you life expectancy is to eat a diet which contains just enough calories to provide for your daily needs. Experiments on flies, monkeys and even people consistently show that low calorie diets like this can significantly increase your life expectancy, possibly by as much as 30%.

As you know, the big bang is how the universe first began. It began from a single point that expanded in a giant burst/explosion of matter and energy. The first evidence this happened is that the universe is still expanding. All the galaxies in the universe are moving away from each other. Imagine that these galaxies are drawn onto the surface of a balloon and that balloon is being blown up. Working backwards - shrinking your balloon - they must have come from one point. The real evidence for the big bang is that the universe is filled with very weak radio waves. This is the remains of the very first light the universe ever emitted and its called cosmic background radiation (CBR). Think about the early universe as a "soup" of particles that were so dense and so close together, that light kept bouncing off them and couldn't escape. But as this mass of particles expanded, they became less dense until they reached a point at which light could escape. So the universe switched on like a lightbulb. And we can see the evidence of that "first light" today! CBR was first detected by a couple of electrical engineers - Penzias and Wilson - in 1965. They were just doing radio measurements and they thought they had a faulty piece of kit ! But they'd just detected the birth of the universe! It's not every day you do that. So there you are - we know that the big bang happened. But no-one knows why it happened!