TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Corals are _ fold.

SOLUTION: two

PROBLEM: Reverse osmosis uses three to ten gallons of water to produce _ gallon of drinking water.

SOLUTION: one

PROBLEM: Pets also track in pollen, and one out of every _ people is allergic to cat or dog dander.

SOLUTION:
ten