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

[EX Q]: Vitamins are classified into _ groups.
[EX A]: two

[EX Q]: Granite weathers one inch in _ thousand years.
[EX A]: ten

[EX Q]: Most indoor gyms space their protection bolts often less than _ feet apart.
[EX A]:
five