Five simple questions science CAN'T ANSWER

Humans are pretty smart. Apart from our special skill of wiping out large parts of our own population and several other species, we've achieved some pretty remarkable things.


But there's a lot. Like, a LOT of stuff that we still don't know. Some of it is surprisingly simple - the answer must be staring us in the face - and yet we just haven't worked it out yet. So here's our top five list of stuff we should know, but don't.