How much does your head weigh? : the big book of facts

"This funny, informative bind-up of three successful books, ALL of them Silver Birch Award Winners or finalists - You Asked for It!, Funny You Should Ask and Ask Me Anything! - is now reissued with updated stats and information and a bright new cover. Why is 13 unlucky? Why don't tattoos come off? Do twins have the same DNA? Why is it called a funny bone? What did we use before toilet paper? Do animals dream? Why can't you tickle yourself? Almost...