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

[Q]: Planaria has rudimentary eyes which produce _ images but detect direction.
[A]: no


[Q]: Dingoes live to _ or six years of age in the wild and fifteen years in captivity.
[A]: five


[Q]: Most people go back to work within one to _ months after having a heart attack.
[A]:
three