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.

Prions are protein molecules which have ____ metastable states.
two

R is an average of the color rendering ability of ____ or more specific colors.
eight

Lines of force are ____ dimensional, surrounding a bar magnet on all sides.

three