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

[EX Q]: Sierra County has _ different regions.
[EX A]: two

[EX Q]: All dogs are animals, and no cats are dogs, therefore _ cats are animals.
[EX A]: no

[EX Q]: Postzygotic isolation exists between the _ frog species.
[EX A]:
two