instruction:
You will be given a passage, and your task is to generate a Yes/No question that is answerable based on the given passage.
question:
The Greatest Showman is a 2017 American musical film directed by Michael Gracey in his directorial debut, written by Jenny Bicks and Bill Condon and starring Hugh Jackman, Zac Efron, Michelle Williams, Rebecca Ferguson, and Zendaya. The film is inspired by the story of P.T. Barnum's creation of the Barnum & Bailey Circus and the lives of its star attractions.
answer:
was the greatest showman based on barnum and bailey?


question:
As the governing body of association football, FIFA is responsible for maintaining and implementing the rules that determine whether an association football player is eligible to represent a particular country in officially recognised international competitions and friendly matches. In the 20th century, FIFA allowed a player to represent any national team, as long as the player held citizenship of that country. In 2004, in reaction to the growing trend towards naturalisation of foreign players in some countries, FIFA implemented a significant new ruling that requires a player to demonstrate a ``clear connection'' to any country they wish to represent. FIFA has used its authority to overturn results of competitive international matches that feature ineligible players.
answer:
do you have to be a citizen to play in fifa?


question:
According to the theory of relativity, no information can travel faster than the speed of light in vacuum, but this does not mean that the refractive index cannot be lower than 1. The refractive index measures the phase velocity of light, which does not carry information. The phase velocity is the speed at which the crests of the wave move and can be faster than the speed of light in vacuum, and thereby give a refractive index below 1. This can occur close to resonance frequencies, for absorbing media, in plasmas, and for X-rays. In the X-ray regime the refractive indices are lower than but very close to 1 (exceptions close to some resonance frequencies). As an example, water has a refractive index of 6999999999740000000♠0.99999974 = 1 − 6993260000000000000♠2.6×10 for X-ray radiation at a photon energy of 6985480652946099999♠30 keV (0.04 nm wavelength).
answer:

can a refractive index be less than 1?