TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Plasma levels fall by about a half within three to _ hours.

SOLUTION: four

PROBLEM: Humans begin laughing at _ to three months of age.

SOLUTION: two

PROBLEM: Most people have five fingers on each hand and _ toes on each foot .

SOLUTION:
five