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

[EX Q]: Degradation is a result of _ simultaneous processes.
[EX A]: two

[EX Q]: Stroke is our nation's number _ killer, and a leading cause of disability for older adults.
[EX A]: three

[EX Q]: All human beings come from _ cells.
[EX A]:
two