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.

Fire occurs any time ____ elements are present - fuel, heat, oxygen and the chemical chain reaction.
four

Pyrimidines contain ____ ring and purines contain two rings.
one

Breast cancer is the most common cancer among women, accounting for ____ in three cancers diagnosed.

one