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]: Most people go back to work within _ to three months after having a heart attack.
[EX A]: one

[EX Q]: Crawlers are minute, orange-yellow and oval, with six legs and _ pair of antennae.
[EX A]:
one