TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Infertility affects one in _ couples and affects both men and women.

SOLUTION: seven

PROBLEM: Zeolites have basically _ different structural variations.

SOLUTION: three

PROBLEM: Malignant tumors are more dangerous, and survival times can range from _ months to several years.

SOLUTION:
six