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]: Earthquakes are most frequent where ____ or more plates meet.
[A]: two


[Q]: Developed economies have all ____ legs of the stool needed to support capitalist enterprise.
[A]:
three