Test your thumb knowledge

http://www.bbc.co.uk/news/uk-england-37498017

Version 1 of 2.

Artist David Shrigley hopes a giant "thumbs up" sculpture - unveiled on the Fourth Plinth in Trafalgar Square earlier - will make people feel more positive about their lives.

But how much do you know about thumbs? Answer the true or false questions below with either a "thumbs up" or a "thumbs down".