In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
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Question: Allergic rhinitis is the most common allergic disease, with one in _ Canadian adults affected.

Answer: five

Question: Y are _ morphisms and g is quasi-compact and surjective.

Answer: two

Question: Arthropods are made up of _ groups of living animals and one group of extinct animals.

Answer:
four