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

[Q]: Urushiol oil can be active on any surface for _ years and possibly longer.
[A]: five


[Q]: Cockroaches require food every _ to ten days but mut take in water every ten days.
[A]: seven


[Q]: Corals only grow by _ centimetres a year.
[A]:
two