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.

[EX Q]: Beryllium has ____ protons and four electrons.
[EX A]: four

[EX Q]: Fitness has ____ components, aerobic and muscular.
[EX A]: two

[EX Q]: Pyrimidines contain ____ ring and purines contain two rings.
[EX A]:
one