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

[EX Q]: Chlorine is manufactured in _ ways.
[EX A]: two

[EX Q]: Beavers have an average of _ young once a year.
[EX A]: four

[EX Q]: Fruit flies have three pairs of autosomes and _ pair of sex chromosomes.
[EX A]:
one