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

[Q]: Fire extinguishers have _ parts.
[A]: seven


[Q]: Pollination is accomplished only by insect-agency, and where insects fail _ fruits are ripened.
[A]: no


[Q]: Clovers occasionally have leaves with _ leaflets, instead of the usual three.
[A]:
four