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]: Ozone is formed of ____ atoms of oxygen.
[EX A]: three

[EX Q]: Human malaria is caused by ____ species of Plasmodium . .
[EX A]: four

[EX Q]: Anthropology is comprised of ____ sub-fields.
[EX A]:
four