Misc: Seventy percent of house dust is made up of dead -----------------------?

Questions

In which country was the first modern motorway created?

Which British Prime Minister wrote the novels Coningsby and Sybil?

In Blue Grass music who is Flatt's partner?

In Britain what is the background colour on road signs on Motorways?

In the game of Cluedo what is the name of the Reverend?