Misc: More people use ______ toothbrushes, than red ones?

Questions

Undershot, overshot and breastshot are what kinds of mechanical device?

Which science fiction writer in his 1972 book The Lost Worlds of 2001 wrote -Any sufficiently advanced technology is indistinguishable from magic?

Which aeronautical engineer designed the Scneider Trophy winning Supermarine S6 seaplanes and the spitfire?

What was the anme of the first commercial hovercraft designed by Christopher Cockerell?

What is the name of the process by which metal particles are compressed into a solid body under heat lower than melting point?