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.

Cytochrome oxidase consists of two cytochromes and ____ copper atoms.
two

Beryllium has ____ protons and four electrons.
four

Radial pulse is felt with the first ____ fingers, the index, middle and ring fingers.

three