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

[EX Q]: Frozen grafts can have a shelf life of up to _ years.
[EX A]: five

[EX Q]: Titanium is found in column _ along with chemically similar zirconium, hafnium, and thorium.
[EX A]: four

[EX Q]: American men click on Internet sex sites _ times more often than women do.
[EX A]:
six