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.

[Q]: Marine biologists have ____ theories on why whales breach.
[A]: two


[Q]: Rabbinic literature is made up of ____ major kinds of works.
[A]: five


[Q]: Tin exists in ____ allotropic forms.
[A]:
three