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

[EX Q]: Arthritis is the leading cause of disability in the state affecting about one in _ adults.
[EX A]: three

[EX Q]: Yeasts are of _ kinds.
[EX A]: two

[EX Q]: Many babies improve before _ years of age.
[EX A]:
two