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

[EX Q]: Falcons are roughly divisible into three or _ groups.
[EX A]: four

[EX Q]: Digoxin works in _ ways.
[EX A]: two

[EX Q]: Melanocytes are dendritic and are distributed roughly one per _ basal cells.
[EX A]:
six