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

[EX Q]: Most people see the world through _ types of visual-receptor cells.
[EX A]: four

[EX Q]: Cardinals are approximately _ and three fourths inches in length.
[EX A]: eight

[EX Q]: Most population cycles are about three to _ years in duration.
[EX A]:
four