In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[Q]: Corms are undifferentiated, uniform, and contain _ rings when cut apart.
[A]: no

[Q]: Knives have _ cutting edges for double cutting life.
[A]: two

[Q]: Breast cancer is a common disease, affecting one in _ women during their lifetime.
[A]:
nine