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

[EX Q]: Sake contains _ preservatives or sulfites.
[EX A]: no

[EX Q]: Hoatzin has typical foot with _ toes forwards and one backwards.
[EX A]: three

[EX Q]: Fish are sexually mature at age _ and six year old fish are common.
[EX A]:
three