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

[Q]: Black adults have three to _ times greater incidence of bacteremia, compared with white adults.
[A]: five


[Q]: Prolactin exists in _ heterogenic forms which possess varying biological activity.
[A]: three


[Q]: All compound microscopes contain _ magnifying lenses and work similarly.
[A]:
two