In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
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Question: Female cats can go into heat for the first time as early as _ months of age.

Answer: five


Question: New species are believed to arrive in the Mediterranean at the rate of _ to five annually.

Answer: four


Question: Cardiovascular events represent important factors during the _ phases of a space mission.

Answer:
three