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

[EX Q]: Liquid crystals lack the full _ dimensional position and orientation order of ordinary crystals.
[EX A]: three

[EX Q]: Smokeless tobacco is used in _ common forms.
[EX A]: two

[EX Q]: Prairie dogs have only _ litter of five pups a year.
[EX A]:
one