You don’t have to be a “super-recogniser” to know that human facial features are extremely varied. Just look around you. Yet look at a most other animals and you’d find it hard to tell individuals apart. So why are human faces so diverse?

We’ll also be finding out why salt tastes salty (warning: lots of spitting and gargling ahead) and one listener wants to know what would happen if one of the key ocean current systems, the North Atlantic Conveyer, slowed down or stopped altogether. Presenter Marnie Chesterton heads to the beaches on the West Coast of Scotland in search of answer.