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

[EX Q]: Carbon dioxide accounts for _ fourths of the predicted increase in the greenhouse effect.
[EX A]: three

[EX Q]: Premolars have one, two, and sometimes _ canals.
[EX A]: three

[EX Q]: Cold Joints Occur where _ separate concrete pours come together.
[EX A]:
two