What percentage of air is composed of nitrogen?

More Questions:

What is the thin layer of foam on top of an espresso called?

What popular architect designed the Guggenheim Museum of Modern Art?

What phrase appears on the ribbon in the bald eagle's beak on a one-dollar bill?

What is stored at a depository in Fort Knox?

What eccentric artist based his famous moustache on that worn by painter Diego Velazquez?

In "The Twelve Days of Christmas', what did my true love send to me on the sixth day?

Which author and philosopher is known for his works The Plague, The Outsider and The Fall?

In 1803 The Louvre was renamed to what?

What three animals are mentioned in Dr. Suess" "Green Eggs and Ham"?

What London square is home to Nelson's Column?

Sofia is the capital of which nation?

What does the Mach number indicate?

Which Actor played Chachi Arcola on the TV show "Happy Days"?

What R&B singer was backed by "The Miracles"?

What TV title character lived at 485 Mapleton Drive, Mayfield?