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

[Q]: Diarrhea is an illness that kills _ and one-half million children per year.
[A]: three


[Q]: Planaria has rudimentary eyes which produce _ images but detect direction.
[A]: no


[Q]: Cleavage is very poor in _ directions.
[A]:
two