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]: Differentiation is caused by the energy going in ____ directions.
[A]: two


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


[Q]: Crabs have ____ pairs of gills.
[A]:
nine