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]: Box turtles are mature and capable of mating at ____ years old.
[A]: five


[Q]: Romantic love involves ____ people.
[A]: two


[Q]: Crabs are crustaceans with ____ pairs of legs.
[A]:
five