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.

Raindrops produce ____ types of sound underwater.
two

Cellulose contains nothing that is considered hazardous, and carries ____ hazardous warning messages.
no

Physical hunger is a physiological process that occurs every three to ____ hours.

four