instruction:
In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
question:
Sewage travels through _ different sets of pipes.
answer:
three

question:
Retinoic acid regulates oral epithelial differentiation by _ mechanisms.
answer:
two

question:
Most movements require the activation of very few muscles, around _ percent or ten at the most.
answer:
five