Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Q: Birds have ____ basic types of feathers.

A: three
****
Q: Tobacco companies account for ____ of the five biggest billboard advertisers in the country.

A: four
****
Q: Air temperature can fall below ____ in the mountain summit area and snowfall is common in winter.

A:
zero
****