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.

Atoms are extremely small, on the order of a few ____ billionths of a meter.
ten

Rabbits have ____ incisors in the upper jaw where rodents have only two.
four

Most infected persons have ____ symptoms of disease.

no