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

[EX Q]: Plants grow to _ feet tall with feathery, smoky purple foliage.
[EX A]: four

[EX Q]: Diffusion occurs between the capillaries of the _ blood supplies.
[EX A]: two

[EX Q]: Some scholars question the existence of the first _ emperors.
[EX A]:
nine