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

[Q]: Ozone leaves _ by-products except pure oxygen.
[A]: no


[Q]: Armaments manufacturers use lithium to produce tritium in _ ways.
[A]: two


[Q]: Snapdragons are annual flowering plants that grow one to _ feet and thrive on sunshine.
[A]:
four